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Hemmi Slide Rule Catalogue Raisonné
by Paul Ross
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The Hemmi Catalogue Raisonne (both parts I and II) by Paul Ross of the SRTCo.us is being preserved at ISRM.

This Catalogue Raisonne describes every slide rule ever made by the Hemmi Slide Rule Company of Japan--or at least all those I have been able to identify. It is the most comprehensive catalogue of Hemmi slide rules ever published. There are two parts (1) This page lists Hemmi slide rules for which a model number is known. (2) The second page contains descriptions of Hemmi-made slide rules for which I have not been able to determine a model number. They are usually rules with names rather than numbers or military rules or rules sold under another company's (Post, Foxboro, SKF, etc.) name.
Construction material is celluloid on bamboo except for model numbers which begin with "P" (e.g., "P23") which are all plastic and for a few rules whose substance is explicitly mentioned in the text.
This is an updated version of the Comprehensive Hemmi Catalog which was published in the Spring 2003 issue of the Journal of the Oughtred Society. It is based upon about 500 documents, photographs and specimen slide rules, many of which were supplied by my friends in Japan: William Lise, Atsushi Tomozawa, Yukio Kubota and Hitoshi Nori; I cannot begin to express my gratitude to them. Many errors exist in spite of their efforts and this catalog remains a work in progress. I will be grateful to anyone who can supply missing information or pictures or point out errors. I am indebted to Tom Dilatush for prolonged discussions of how this information should be organized and displayed.
You may also be interested in A Hemmi Chronology. It lists the important dates and shows how markings on Hemmi rules changed from time to time.

Paul Ross, Feb 2022
Model
 		Dates
Front Scales
 Rear and Other Calculating Scales
 Body
 Comment
 Also Sold As
Models1-18: Obsolete Model Numbers Abandoned About 1930.
1
1/1
 		1913-29
 Pic
 A [B, C] D
 [S, L, T]
//Closed||
250 x 28 x 9.5 mm		 Mannheim. ("Normal") Listed as obsolete starting in 1936 but price listed in Hemmi catalogs through 1937 and available from Frederick Post (as model 1449) through 1940.
 Tamaya 1941 (1916-27);
H-O 1768 (-1914-);
Post 1449 (1930-WWII)

Pic
 Artillery variant with minutes and mils conversion scales on bottom edge and trigonometric formulas for gunnery on back of rule. Dates probably later than model 1.

Pic
 A [B, Stadia, C] D
 Stadia variant. Stadia scale (SinCos and Cos²) added to front of slide. Dates probably later than model 1.
2
 		1913-29
 Pic
 Same as model 1 but with decimal-indicating cursor. //Closed||
250 x 28 x 9.5 mm
 Discontinued ca1929.
Tamaya 1937 (1913-27);
H-O 1767 (-1914-28-)
3
 		1919-29
 Pic
 LL2, A [B, C] D, LL3
 [S, L, T]
Gutter: E, F
 //Closed||
250 mm
x 1½ in x 10 mm
 Electro. (Copy of Faber 378) LL scales keyed to offset W gauge mark. E,F scales separated in gutter. No over-range. HP gauge mark (probably only 746). Single hairline. At least three different cursors. Tamaya 1905 (1919-27); H-O 1770 (1928), Hemmi 80 (1930+).
4
 		1919-29
 Pic
 Same as 3 but with decimal-indicating cursor.
Tamaya 1904 (1916-27), Hemmi 81 (1930+
5
 		1919-29
 Pic
 A [B, C] D
 [S, L, T]
//Closed||
500 mm x 1¼ x 13/32 in
 Listed as obsolete by Hemmi in 1936 but price listed through 1937. In Post catalog (model 1450) until WWII and in H-O catalog (model 1772) though1948.
 Tamaya 1899 (1916-27);
H-O 1772 (1928);
Post 1450 (1936-WWII).
6
 		1919-29
 Pic
 A [B, C] D
 [S, L, T]
//Closed||
125 x 24 x 9 mm
 Pocket Mannheim. Replaced by model 48 ca1930. H-O 1763 (-1914-35);
Tamaya 1942 (1916-27).
7
 		1926-29
 Pic
 Same as 6 but with decimal-indicating cursor
Tamaya 1949 (1927)
8
 		1913-29
 Pic
 A [B, C] D
 [S, L, T]
/Closed||
125 x 24 x 9 mm 		Extra Fine Mannheim w Magnifier.
Tamaya 1943 (1916-27);
H-O 1764 (-1914-48-)
9
 		1919-29
 Pic
 Same as 8 but with magnifiying decimal-indicating cursor
Discontinued ca1929.
 Tamaya 1900 (1916-27)
10
 		1926-29
 Pic
 A [B, C] D
 [S, L, T]
//Closed||
250 mm
 Ten-inch extra fine with "extended lens" magnifier. Discontinued ca1929.
 Tamaya 2148 (1927)
11
 		1926-29
 Pic
 Same as10 but with decimal-indicating "extended-lens" cursor.
Discontinued ca1930.
 Tamaya 2180 (1927)
12
NA
 DF [CF, CI, C] D
(Folded at ?)
 		Blank
 ?
150 mm
 Simplified Slide Rule. Plastic.
Single uncorroborated reference.
12
 		1926-29
 Pic
 Same as model 3 but with "extended-lens" magnifying cursor.
 Discontinued ca1929.
 Tamaya 2782 (1927)
13
 		1926-29
 Pic
 Same as 4 but with decimal-indicating "extended-lens" cursor.
 Discontinued ca1929.
Tamaya 2783 (1927)
14
 		1926-29
 Pic
 A [B, C] D
 [S, L, T]
||Closed||
100 mm
x 11/16 x 7/32 in 		Vest Pocket Mannheim with square edges.
 Tamaya 2784 (1927);
Hemmi 35 (1930+)
15
 		1926-29
 Pic
 Same as 14 but with decimal-indicating cursor.
 Discontinued ca1929.
Tamaya 2785 (1927)
16
 		1926-29
 Pic
 Same as 14 but with magnifying cursor.
 Discontinued ca1929.
 Tamaya 2786.
Hemmi 35ML (1930+)
17
 		1926-29
 Pic
 Same as 14 but with magnifying decimal-indicating cursor.
 Discontinued ca1929.
 Tamaya 2787
18
 		1826-29
Pocket kit including pen, pad and model 15 slide rule. Discontinued ca1929.
Tamaya 2788
19
 		1927
 Pic
 A [B, C] D
 [S, L, T] ?
 250 mm
 Student version of model 1. Model number may have been changed to 40 before any were actually sold.
Model Numbers 20-24 were assigned to Classroom Demo Slide Rules before WWII; Student Rules after WWII.
20 1932-42
 NA
 A [B, CI, C] D, K
 [S, L, T]
Demo
2000 mm
 Demonstration Mannheim (Model 50)
 Tamaya 4451 (1932)
21
 		1932-42
 NA
 K, A [B, CI, C] D, L with over-range
 [S, S&T, T]
 Demo
2000 mm
 Demonstration Rietz (Model 64).
Tamaya 4452 (1932)
22
 		1951-59
 Pic
 [CI, C] D, A
 No back
 Special
200 x 23
x 9 mm
 Cheap student rule distributed in Asia only. Slide held to single stator. Some (1955 only?) sandalwood, not bamboo. Celluloid cursor.
P23
 		1957-69
 Pic
 A [B, CI, C] D
 A [B, CI, C] D
 Open
180 mm
x 1 x 1/8 in
 Student Mannheim w CI scale.
Hemmi's first plastic-based rule.
24
 		1927
 Pic
 A [B, C] D
 Blank
//Closed||
125 x 26 x 3 mm
 Ultra-thin all plastic with celluloid cursor. 13 cm scale on top edge; bottom blank. Identical to model 34 except imprinted with advertising. Rare. Appears in no known catalog.
P24
 		1963-69
 Pic
 DF [CF, CI, C] D, A
Folded at √10.
 Blank
 Open
180 mm x 1 x 1/8 in
 Student.
Models 30-39: Miscellaneous Four- and Five-inch Closed Body Slide Rules
30
 		1930-43
 Pic
 A [B, C] D
 [S, L, T]
//Closed||
100 mm x 11/16 x 7/32 in 		Vest Pocket Mannheim. Model number never appears on rule. Some w "SUN" cut through or "SKF" embossed into backing plate. 1000¥ ($2.78) in 1969.
 Tamaya 4453 (1927);
Post 1447 (1931-33);
Post 1440 (1934-WWII)
31
 		1930-42
Pic
 Same as 30 but with decimal-indicating cursor.
 No CI scale
 Tamaya 4454
32
 		1930-42
 Pic
 Same as 30 but with magnifying cursor. Tamaya 4455; Post 1447M (1931-33); 1441 (1934-WWII);
Boston Blue Print 1441; US Blue 1888.
33
 		1930-42
 Pic
 Same as 30 but with decimal-indicating magnifying cursor
 No CI scale
 Tamaya 4456
30R
 		MIOJ-1950
 Pic
 A [B, CI, C] D [S, L, T]
(S keyed to A/B except WWII-1955 keyed to C/D) 		//Closed||
100 mm x 11/16 x 7/32 in 		Vest Pocket Mannheim w CI scale. No model number on rule but case and box marked "30R."
 Fuji 41.
Post 1440.  
30
 		1951-EOB
 Pic
 Same rule with "R" dropped from model number on case and box. All-plastic cursor after ca 1970.
32R
 MIOJ-1950
 Pic
 Same as 30R but with magnifying cursor
Post 1441(WWII-1971);   T-P 44DA-410 (1972+);
H-O 1760 (-1952-64);       Geo 341-3405 (1964+)
US Blue 1888 (MIOJ)
32
 1951-EOB
 Pic
 Same as 30 but with magnifying cursor.
P33S
 		1971
 Pic
 A [B, CI, C] D, K
 [S, L, T]
(S keyed to C/D)
 Closed
125 x 28 x 5 mm
 Pocket Improved Mannheim. All-plastic version of model 34RK.
P33/SS
 		1970
 Pic
 A [B, CI, C] D, K
 [S, L, T]
(S keyed to C/D)
 Closed
125 x 27 x 4.5 mm
 Pocket Improved Mannheim. Unique size.
 Geotec 341-3610
34
 		1932
 Pic
 A [B, C] D
 Blank
 //Closed||
125 x 26
x 3 mm
 Ultra-thin all plastic with celluloid cursor. 13 cm scale on top edge; bottom blank
 Hemmi 24;
Tamaya 4457
34P

 		1932-42
 NA
 A [B, C] D Blank //Closed||
125 mm x 15/16 x 5/32 in
 Thin Pocket Mannheim with blank back.
 Post 1443 (1931-WWII)
MIOJ
 Pic
 //Closed||
125 x 26 x 5 mm
34π

 		1932-42
 Pic
 CF [DF, CI, C] D
Folded at π 		[S, L, T]
(S keyed to C/D) 		//Closed||
125 mm x 15/16 x 5/32 in
 Thin Pocket Mannheim with folded scale.
 Post 1444 (c1935-WWII);
H-O 1762 (-1935-WWII)
MIOJ
 NA
 //Closed||
125 x 26
x 5 mm
34R

 		1935-40
 Pic
 A [B, CI, C] D [S, L, T]
(S keyed to A/B except WWII-1955 keyed to C/D) 		//Closed||
125 mm x 15/16 x 1/8 in
 Thin Pocket Mannheim w CI Scale.
 Post 1444 (c1935-WWII);
H-O 1762 (-1935-WWII)
1955-68 NA
 //Closed||
125 x 26
x 5 mm
34RK
 		1936-EOB
 Pic
 A [B, CI, C] D, K
 [S, L, T]
(S keyed to A/B except WWII-1955 keyed to C/D)
//Closed||
125 x 26
x 5 mm
 Post 1444K (1937-70),1444(1971); T-P 44DA-440 (1972+);
US Blue 1887 (1930s); H-O 1762 (WWII-64); Geo 341-3425 (1964+).
34T
 		1936-42
 Pic
 A [B, C] D
 [S, L, T]
//Closed||
125 mm x 15/16 x 1/8 in
 Thin Pocket Mannheim. "SUN" or ASEA embossed into backing plate.

35
 		1935-48
 Pic
 A [B, C] D
 [S, L, T]
||Closed|| 100 mm x 11/16 x 3/16 in
 Vest Pocket Mannheim with 4-inch and 10-cm measuring scales on square edges Hemmi 14;
Post 1437 (c1935-WWII);
H-O 1761 (-1935-48-)
35ML
 		1930s
 Pic
 Same as 35 but with magnifying cursor Hemmi 16
P35
B35
 		1959-61
 Pic
 K, DF [CF, CI, C] D, A
Folded at √10.
 Blank
 Open
115 mm x 1 x 1/8 in
 Marked "B35" (factory error for "P35"?); thin bamboo core covered with PVC (not celluloid); scales printed (not engraved).  All known specimens also marked H-O 1759.
P35S
 		1971
 Pic
 K, DF [CF, CI, C] D, A
Folded at √10.
 [LL1, LL2, LL3]
 Closed
125 x 28 x 4.6 mm

36
 		1936-WWII
 Pic
 A [B, CI, C] D
 [S, L, T]
Closed
125 mm x ¾ x 7/32 in
 Narrow Pocket Mannheim w CI scale. Measuring scales on BACK of rule.
Post 1438 (c1935-WWII)
P36
P36S
 		1966-70
 Pic
 D [Conversion gauge marks, A] D
 Instructions [Conversion gauge marks, B] Instructions
 Open
115 mm x 1 x 1/8 in
 Rule is labeled "P36;" box and instructions "P36S." Set arrow on slide opposite value on top D scale; converted value appears on bottom D scale opposite corresponding arrow. Reverse slide for more conversions. Markings and instructions in Japanese. 450¥ ($1.25) in 1969.
P37
 		1966-70
 Pic
 (1), (2), D [C, CI, B] MD1, MD2
 [B, PR1, PR2, PR3]
Closed
125 x 28 x 4.6 mm
 SALES. Labeled in Japanese. MD1 is months and days from 1/1 to 6/30, MD2 from 7/1 to 12/31. PR1-2-3 = three short profit ratio scales. Reverse slide to read B, PR scales.. {Two hairlines: D: 1.2}. 700¥ ($1.94) 1969.
P39
NA
 K, A, DF [CF, CIF, CI, C] D, DI, L
Folded at ?
 [B, TI, SI, C]
 Closed
125 mm
 Single uncorroborated reference.
Models 40-49: Basic Mannheim Rules (A [B, C] D) before WWI and "Improved" Mannheim (A [B, CI, C] D, K) after WWII.
40
 		1932-49
 Pic
 		A [B, C] D
 [S, L, T]
Closed
250 x 28 x 8 mm
 Tamaya 4458 (1927), Post 1446 (1931-49); H-O 1768 (-1935-48-); Boston Blue Print 1446; US Blue 1876 (1930s); Lietz 2974N (1930s).
41
 		1932-42
 Pic
 		A [B, C] D
 [S, L, T]
Closed
125 mm
 Pocket Mannheim. No measuring scales Tamaya 4459 (1932)
42
 		1932
 Pic
 		A [B, C] D
 [S, L, T]
Closed
250 x 28 x 8 mm 		Model 40 w measuring scales on BACK. Tamaya 4460 (1932)
43
 		1932
 NA
 		Same as 42 but with decimal-indicating cursor.
 		Tamaya 4461 (1932)
44
 		1932
 Pic
 		A [B, C] D
 [S, L, T]
 Closed
125 mm x 15/16 x ¼ in
 No slant; cm & inch scales on back of rule. Tamaya 4462 (1932)
45
 1932 NA
 		Same as 44 but with decimal-indicating cursor. Tamaya 4463 (1932)
45
 		1949-68
 Pic
 		DF [CF, CI, C] D, A
Folded at √10.
 [TI, L, SI]
Closed
200 x 28 x 8 mm
 Student. Quite different from 1932 model 45.
46
 		1936-42
 Pic
 		A [B, C] D
 Blank
 Special. 125 mm x 1 in
 "Cardboard covered in transparent celluloid with leather sheath."
47
 		1936-42
 Pic
 		A [B, C] D
 [S, L, T]
//Closed||
250 x 28 x 8 mm
 Thin successor to model 1/1.
 Post 1449T (1937-WWII)
48
 		1932-42
 Pic
 		A [B, C] D
 [S, L, T]
//Closed||
125 mm x 15/16 x ¼ in
 Pocket Mannheim. Thin successor to model 6.
40F
 		1968-69
 Pic
 K, DF [CF, CI, C] D, A
Folded at √10
 [TI, L, SI]
 Closed
250 x 28 x 8 mm
Fuji 85.
40RK

 		1949-69
 Pic
 A [B, CI, C] D, K
 [S, L, T]
(S keyed to A/B except Staedtler 944-55 keyed to C/D)
 Closed
250 x 28 x 8 mm
 Improved Mannheim. ("Slide Rule with CI and K Scale" in early literature)

Post 1447 (c1949-1971);
H-O 1768C (-1952-64);
Geo 341-3526 (1964-71);
US Blue 1877 (1940s?).
1973
 Pic
 		Same as preceding but wider with thick plastic back. Closed
250 mm x 1¼ x 9/32 in
 T-P 44BA-470 (1972+);
H-O 341-3526 (1972+)
40-50
Pic
 Overhead projection rule for Hemmi model 40RK. Projection 305 x 182 x 12 mm

P
40RK
 		1967-69
 Pic
 A [B, CI, C] D, K
 [S, L, T]
Open
250 x 28 x 8 mm
 All-Plastic Improved Mannheim. Hard plastic case.
 Post 1447P (c1967);
Geo 341-3530 (c1967)
43A
 		1961-71
 Pic
 A [B, CI, C] D, K
 [T, L, S]
(S keyed to C/D)
 Closed
200 x 28 x 8 mm
 Student Improved Mannheim.
P43D
 		1973-EOB
 Pic
 A [B, CI, C] D, K
 [T, L, S]
(S keyed to C/D)
 Closed
200 x 28 x 6.4 mm
 Like 43S except no indices on back of rule; slide must be reversed.
P43S
 		1969
 Pic
 		A [B, CI, C] D, K
 [T, L, S]
(S keyed to C/D)
 Closed
200 x 28 x 6.4 mm
 Plastic version of 43A. Indices for reading trig scales on back of rule.

45K
 		1962-EOB
 Pic
 K, DF [CF, CI, C] D, A
Folded at √10.
 [TI, L, SI]
 Closed
200 x 28 x 8 mm
 Post 1445 (c1966-71); T-P 44BA-450 (1972+);
Geo 341-3500 (1967+).
All have scales folded at π.
P45K
 		1965-69
 Pic
 K, DF [CF, CI, C] D, A
Folded at √10.
 [TI, L, SI]
Open
200 x 28
x 5 mm
 Open body all-plastic version of 45K
 Post 1445P (-1965-)
Scales folded at π.
P45D
 		1973-EOB
 Pic
 K, DF [CF, CI, C] D, A
Folded at √10.
 [T, L, S]
 Closed
200 x 28 x 6.4 mm
 "Junior High School Students." Like P45S except trig scales not inverted and no indices on back of rule; slide must be reversed.
P45S
 		1969-73
 Pic
 K, DF [CF, CI, C] D, A
Folded at √10.
 [TI, L, SI]
Closed
200 x 28 x 6.4 mm
 Closed body all-plastic version of 45K. Simpler construction than P45K.
Models 50-59: "Improved" Mannheim Slide Rules (A [B, CI, C] D, K and [S, L, T]) and Variants.
50, 50/1,
50/3 		1932-51
 Pic
 		A [B, CI, C] D, K
 [S, L, T]
(S keyed to A/B except WWII-1955 keyed to C/D)
 //Closed||
250 x 28 x 10.5 mm 		Improved Mannheim. Formerly model 102.
 Hemmi 102; Tamaya 4464 (1932); Post 1452 (c1935-51); H-O 1771 (-1928-48-);
US Blue 1880 (1930s).
50F, 50/1F
 		1936-MIOJ
 Pic
 		A [B, CI, C] D, K
 [S, L, T]
//Closed||
250 x 28 x 8 mm
Thin version of 50, 50/1 but accepts standard cursor.
 Post 1452T (1936-WWII).
50π/1
 		1936-42
 Pic
 		A, DF [CF, CI, C] D, L
Folded at π.
 [S, S&T, T]
//Closed||
250 x 28 x 10.5 mm
Post 1455 (c1935-WWII).
50W 1951-EOB
(For Post)
 Pic
 		A [B, CI, C] D, K
 [S, L, T]
(S keyed to A/B except WWII-1955 keyed to C/D)
 //Closed||
250 x 34 x 11 mm		 Wide Improved Mannheim.
Post 1452W ('51-70), 1452 ('71); T-P 44BA-520 ('72+);
H-O 1771 ('51-64);
Geo 341-3215 ('64+).
P50
 		1965?-68?
 NA
 A [B, CI, C] D, K
 Blank
 Open?
250 mm x 1½ in
 Improved Mannheim.
50-20

 		1935-48
 Pic
 A [B, CI, C] D, K
 		[S, L, T]
//Closed||
500 x 34 x 11 mm
Long Improved Mannheim. Made for Post & H-O only; not sold as Hemmi brand.
 Post 1454 (-1936-WWII);
H-O 1772 (-1935-58-)
H-O 341-3235 (-1969-).
WWII-1969
 Pic
 //Closed||
500 x 40 x 12 mm
 Wide Long Improved Mannheim. Hemmi & Post brands.
{Three Hairlines: D: C, C}.
51/1, 51/3
 		1932-42
 Pic
 		Same as 50/1, 50/3 but with decimal-indicating cursor.
Formerly model 103. Tamaya 4466, 4467 (1932).
52
 		1932-42
 Pic
 		A [B, CI, C] D
 [S, L, T]
//Closed||
125 mm x 15/16 x 11/32 in 		Thicker than 34R.

 		Tamaya 4468;
Post 1448 (1936-37).
53
 		1932-42
 Pic
 		Same as 52 but with decimal-indicating cursor.
 		Tamaya 4469 (1932).
54
 		1936-42
 Pic
 		A [B, CI, C] D, K
with over-range
 [S, L, T]
//Closed||
150 x 26 x 6 mm 		"Extra Fine Improved Mannheim" with magnifying cursor.
 Post 1453 (c1935-WWII).
55
 		1936-42
 NA
 Same as 54 but without magnifying cursor.


Models 60-79: Rietz Slide Rules ( K, A [B, C] D, L and [S, S&T, T] )
60/1, 60/3

 		1932-3x
 Pic
 K, A [B, C] D, L
 [S, S&T, T]
//Closed||
250 mm x 1¼ x 13/32 in
Rietz. Single line model 60/1 discontinued ca 1930. Tamaya 4470, 4471 (1932)
193x-42
 Pic
 K, A [B, C] D, L
with over-range
61/3
 		1932-42
 NA
 		Same as 60/3 but with decimal-indicating cursor.

62/3
 		1932
 		NA
 		K, A [B, C] D, L
 [S, S&T, T]
//Closed||
150 mm
 Extra Fine Rietz. Tamaya 4472, 4473 (1932)
63/3
 		1932
 NA
 		Same as 62/3 but with decimal-indicating cursor.
64, 64/1, 64/3
 		1932-68
 Pic
 		K, A [B, CI, C] D, L
with over-range
 [S, S&T, T]
//Closed||
250 x 34
x 11 mm
 "System Rietz." {64/3 hairlines: D: C, C} Some w 13-0-13 cm on bottom. Probably without over-range before 1935.
 Tamaya 4474 (1932)
64T
 		1965-71
 Pic
 		K, A [B, BI, CI, C] D, DI, L
with over-range
 [T2, T1, ST, S]
 //Closed||
250 x 34
x 11 mm
 "Super Rietz." {3 hairlines: D: C, C}.
65
 		1932-42
 Pic
 		Same as 64/3 but with decimal-indicating cursor. //Closed||
250 x 34
x 11 mm
Tamaya 4475 (1932)
66
 		1932-68
 Pic
 K, A [B, CI, C] D, L
with over-range
 [S, S&T, T]
 //Closed||
150 x 26
x 9 mm
 Extra Fine Improved Rietz.
{3-line cursor: D: C, C}
Some 8-0-8 cm on bottom.
 Tamaya 4476 (1932)
66F
 		1936-42
 Pic
 Same as 66 but thin.


67
 		1932-42
 NA
 		Same as 66 but with 3-line magnifying cursor.

Tamaya 4477 (1932)
68
 		1932-42
 NA
 		Same as 66 but with 3-line decimal-indicating cursor.

Tamaya 4478 (1932)
69
 		1932-42
 NA
 		Same as 66 but with 3-line decimal-indicating magnifying cursor.

Tamaya 4479 (1932)
70 1932-43
 Pic
 		K, A [B, CI, C] D, L
some with over-range
[S, S&T, T] //Closed||
500 x 34
x 12 mm
 Long Improved Rietz.
{3 hairlines: D: C, C}.

 		Tamaya 4480 (1932)
1951-70
 Pic
 		//Closed||
500 x 40
x 12 mm
72
 		1966-71
 Pic
 		K, DF [CF, CIF, CI, C] D, A
with over-range
Folded at √10.
[TI2, TI1, L, SI]
 //Closed||
500 x 40
x _ mm
 "Precision Slide Rule for Practical Engineers." Single hairline.
74
 		1937-EOB
 		Pic
 		K. A [B. CI. C] D, L
with over-range
 		[S, S&T, T]
//Closed||
125 x 26
x 5 mm
 Pocket Improved Rietz.
{3 hairlines: D: C, C}.
Models 80-89: "Electro" Slide Rules
80
80/1
80/3 		1930-32
 		Pic
 		LL2, A [B, CI, C] D, LL3
No over-range
No over-range
[S, L, T]
E, F widely separated in gutter.

 		//Closed||
250 mm x 1 ¼ in x 10 mm
 Electro. LL scales keyed to offset "W" gauge mark. No over-range. Same as model 3 with CI scale added. Hemmi 3;
Tamaya 4481, 4482 (1932);
H-O 1770 (-1928-c50);
Post 1456 (c1934-WWII)
1932-33
 		Pic
 		//Closed||
250 x 34 x 11 mm 		Same as preceding but on slightly wider body.
1934-36
 		Pic
 		[S, L, T]
E, F close together in gutter

 		Same as preceding but no "W" gauge mark. E, F close together in gutter.
1936-52
 		Pic
 		LL2, A [B, CI, C] D, LL3
with over-range
 Same as preceding but with over-range extensions.
81/1, 81/3
1932-42
 		Pic
 		Same as 80/1, 80/3 but with decimal-indicating cursor. Details vary depending upon date of manufacture.  See model 80.
 Hemmi 4;
Tamaya 4482, 4484 (1932)
82 1932-37
 		NA
 		Same as 80/1 except short. //Closed||
125 x _
x 9 mm



Tamaya 4485 (1932)
83
 		1932-37
 		NA
 		Same as 82 but with decimal-indicating cursor.
 		Tamaya 4486 (1932)
84
 		1932
 		NA
 		Same as 82 but with magnifying cursor.
 		Tamaya 4487 (1932)
85
 		1932
 		Pic
 		Same as 82 but with magnifying decimal-indicating cursor. Tamaya 4488 (1932)
85
 		MIOJ
 		Pic
 		db, Neper, A [B, CI, C] D
 [TI2, TI1, L, SI1]
//Closed||
250 x 34 x 11 mm
 Not electro, therefore model number 85 is inappropriate.  {3 hairlines: A: C2, 1.307} (Why 1.307?)
Rare.
80K
 		1953-70
 		Pic
 		E, F, A [B, CI, C] D, LL2, LL3
with over-range
 [S, L, T]
Bottom Edge: K
 //Closed||
250 x 34 x 11 mm
 Electro. K scale on bottom edge; no scales in gutter. No hp mark but different cursors avail for British/US and French/Metric HP. {3-line cursor: A: hp, C2}.
86/3
 		1936-42
 		NA
 		LL2, A [B, CI, C] D, LL3
with over-range
 [S, L, T]
Gutter: E, F
 //Closed||
150 x 26 x 8 mm
 "Extra fine Electro." Hp gauge mark. No W mark. E,F scales close together in gutter. {Three hairlines: A: hp, C2}.

87/3
 1936-42
 NA
 Same as 86/3 but with magnifying cursor.

86/3K
 		1950
 		Pic
LL2, A [B, CI, C] D, LL3
with over-range
 [S, L, T]
Gutter: E, F
Bottom Edge: K
 //Closed||
150 x 26 x 8 mm 		Same as model 86/3 except K scale added to bottom edge.
86
 		1951
 		Identical to and contemporaneous with model 86/3K.
86K
 		1954-70
 		Pic
 		E, F, A [B, CI, C] D, LL2, LL3
with over-range
 [S, L, T]
Bottom Edge: K
 //Closed||
150 x 26 x 8 mm
 "Extra Fine Electro." No scales in gutter, no hp mark. {Three hairlines: A: hp, C2}.
Models 90-99: Stadia Slide Rules
90
 		1932-42
 Pic
 		L, D [M1, M2, C] D, A with over-range [S, S&T, T]
Bottom Edge: K, IA		 //Closed||
250 x 34 x _ mm
 		Stadia. {3 hairlines: D: C, C}. Two calculating scales on bottom edge. IA scale read from offset pointer keyed to rightmost hairline.
90A
 		1940
 NA
 		Same as 90
90B
 		1939?
 Pic
 		Same as 90 but uses "centesimal degrees."
(100 centesimal degrees = right angle)
 		First of a proposed series (models 90B, 91B, 2690B) of centesimal-degree stadia rules. Models 91B and 2690B were never manufactured.
91
 		1932-42
 Pic
 		Same as 90 but with decimal-indicating cursor

Tamaya 4490 (1932)
91A
 		1939?
 NA
 		Same as 91. "91A" used to distinguish this rule from proposed centesimal degree model 91B.
92
 		1932-42
 Pic
 		L, D [M1, M2, C] D, A
 [S, S&T, T]
Bottom Edge: K, IA
 //Closed||
150 x 26 x 9.6 mm 		"Extra Fine Stadia." Two calculating scales on bottom edge. {3 hairlines: D: C, C}. Tamaya 4491 (1932)
93
 		1932-42
 Pic
 		Same as 92 but with magnifying cursor.
 		Tamaya 4491 (1932)
94
 		1932-42
 NA
 		Same as 92 but with decimal-indicating cursor.
 		Tamaya 4491 (1932)
95
 		1932-42
 NA
 		Same as 92 but with decimal-indicating magnifying cursor
 		Tamaya 4491 (1932)
96
 		1936-43
 Pic
 		L, D [M1, M2, C] D, A
with over-range.		 [S, S&T, T]
Bottom Edge: K, IA		 //Closed||
500 x 34 x 11 mm
 Long version of model 90. {3 hairlines: D: C, C}. Two calculating scales on bottom edge. IA scale read from offset pointer keyed to center hairline.
Model Numbers 100-107 were assigned to new rules developed in 1926-27; all were replaced by modern numbering system about 1930.
100
 		1926-27
 Pic
 		A [B, CI, C] D
 [S, L, T]
//Closed||
250 mm
 Short lived.
 Tamaya 2790 (1927)
101
 		1926-27
 Pic
 		Same as 100 but with decimal indicating cursor.
Tamaya 2791 (1927)
102
 		1926-28
 		Pic
 		A [B, CI, C] D, K
 [S, L, T]
//Closed||
250 x 28 mm 		Improved Mannheim. Model number changed to 50/1 ca 1928.
 Tamaya 2792 (1927),
H-O-1771
103
 		1926-28
 Pic
 		Same as 102 but with decimal-indicating cursor.
 		Model number changed to 51/1 ca 1928.
 Tamaya 2793, (1927)
104
 		1927
 Pic
 		LL2, A [B, CI, C] D, LL3
No over-range
 [S, L, T]
Gutter: E, F
 //Closed||
125 mm 		"Pocket Electro." LL scales keyed to offset W gauge mark. E,F scales separated in gutter. No over-range. Hp gauge mark. Hemmi 82;
Tamaya 2994 (1927)
105
 		1927
 Pic
 		Same as 104 but with decimal-indicating cursor. Hemmi 83, Tamaya 2995
106
 		1927
 		NA
 		Same as 104 but with magnifying cursor.
 		Hemmi 84, Tamaya 2996
107
 		1927
 		NA
 		Same as 104 but with magnifying decimal-indicating cursor.
 		Hemmi 85, Tamaya 2997
Models 100-109: Large Classroom Demonstration Slide Rules
100
 		1951-68
 Pic
 		DF [CF, CI, C] D, A
Folded at √10.
 [TI, L, SI]
 Demo
1000 mm
 Demonstration version of model 45.

100K
 		1969-71
 Pic
 		K, DF [CF,CI, C] D, A
Folded at √10
 [TI, L, SI]
 Demo
1000 mm
 Demonstration version of model 45K

101
 		1951-68
 NA
 		ℓ, A [B, CI, C] D
 [S, K, T]
(S keyed to C/D)
 Demo
1000 mm
 Demonstration version of model 2640.
101A
 		1967-EOB Pic
 		A [B, CI, C] D, K
 [S, L, T]
(S keyed to C/D)
 Demo
1000 mm
 Demonstration version of models 40RK & 43A.
102
 		1954-68
 Pic
 		CI, C, [D, A]
 Blank
 Demo
1000 mm
 Demonstration version of model 22.
103
 		1959-EOB
 NA
 		K, DF [CF, CIF, CI, C] D, A
Folded at √10.
 [TI1, TI2, L, SI]
 Demo
1500 mm
 Demonstration version of model 2664S.

104
 		1959-69
 NA

Demo
1000 mm
 Demonstration.

107
 		1969-EOB
 NA
 		LL3, LL2, DF [CF, CIF, CI, C] D, L, LL1     Folded at √10.
 K, A [B, TI1, TI2, SI] D, DI
 Demo
1000 mm
 Demonstration version of model P253.

108
 		1971?
NA
 		LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at √10
 K, A [B, TI, SI, C] D, DI, L
 Demo
1000 mm
 Demonstration version of model 254W.
Models 110-129: Specialty Slide Rules
110
 		1937-MIOJ
 Pic
 		LL2, A [B, CI, C] D, LL3
with over-range
 [S, S&T, T]
Bottom Edge: K
 //Closed||
250 x 34 x 11 mm
 Mechanical /Electrical slide rule. K scale on bottom edge. {Three hairlines: D: C, C}.

120
 		1939?
 Pic
 		L, K, A [B, CI, S1, T1, C] D, SΘ
with over-range
 [LL3, LL3, LL2, LL2, LL1, LL1]
Bottom Edge: GΘ
(2 scales)
 //Closed||
250 x 34 x 11 mm
 "MIGHT." Listed without description by Katsunori Kadokura (Chronology of Japanese Hemmi Slide Rules, Journal of the Oughtred Soc, Vol 1, No 2, August 1992). Pictured specimen identified as Model 120 by Yukio Kubota, March 2014.
DP121
 		1968-69
 Pic
 		LL3, LL2, DF [CF, CIF, CI, C] D, L, LL1
 K, A [B, TI2, TI1, SI] D, DI
 Projection 305 x 182 x 12 mm
 Overhead projection rule for model P253. Sold with five masks for obscuring irrelevant scales.
 ¥10,000 in catalog dated 6911
DP122
 		1968-69
 Pic
 		K, A, DF [CF, CIF, CI] D, DI, L
 K, A, DF [B, TI2, TI1, SI, C] D, DI, L
 Projection 305 x 182 x 12 mm
 Overhead projection rule for models 2662 and 2664S. Sold with five masks for obscuring irrelevant scales.
Models 130-139: Darmstadt Slide Rules (L, K, A [B, CI, C] D, Cos, Sin, Tg and [LL1, LL2, LL3]) and Variants
130
 		1950-69
 		Pic
 		L, K, A [B, CI, C] D, Cos
with over-range
 [LL1, LL2, LL3]
Bottom Edge: SIN, tg
 //Closed||
250 x 34 x 11 mm
 Darmstadt. S and T scales on bottom edge of rule.
{3 hairlines: D: hp-C, C}.
130W
 		1970-72
Pic
 		T, K, A [B, BI, CI, C] D, P, S
with over-range
 [L, LL0, LL1, LL2, LL3]
//Closed||
250 mm x 1½ x 7/16 in
 Advanced Darmstadt. Unique width.
{3 hairlines: A: C2, hp-C2}.
135
 		1959-71
 		Pic
 		T, K, A [B, CI, C] D, P, S
with over-range
 [L, LL1, LL2, LL3]
//Closed||
125 x 26 x 5 mm
 Pocket Darmstadt.
{3 hairlines: D: hp-C, C}.
P135k
 		2005
 		Pic
 		T, K, A [B, CI, C] D, P, S
with over-range
 [L, LL1, LL2, LL3]
 Closed
200 x 32 x 4.3mm
 Darmstadt. Only 250 made. Manufactured by HEMMI in 2005 to specifications of ISRG and Japanese collectors and sold by subscription.
136
 		1951-68
 		Pic
 		L, K, A [B, CI, C] D Cos
with over-range
 LL1, LL2, LL3]
Bottom Edge: SIN, tg
 //Closed||
150 x 26 x 8 mm
Extra Fine Darmstadt. D scale is labeled "SIN" other scales not labeled.

Models 140-149: Pocket Duplex Slide Rules
140
 		MIOJ
 		Pic
 		DF [CF, CI, C] D, L
Folded at √10.
 K, A [B, TI, SI, C] D, DI
 Duplex
150 mm x 1 3/16 x ¼ in
 Hemmi's first "pocket" duplex. Body is short version of old narrow model 150.

141
P141
 		1960-EOB
 		Pic
 		LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at π
 T, S, U, P [Q, c, V, R] A q, n, L
 Duplex
125 x 34 x 4 mm
 Air conditioning duct design. Bamboo (141) and all-plastic (P141) versions. Same blank as 149. All-plastic version marked "'Carrier' Ductuler" (Toyo Carrier Corp). Some bamboo specimens carry no brand name, some marked "Carrier 50210," others marked "Shin Nippon Kucho." (SNK was spun off from Toyo Carrier in 1969.)
143
 		1968-69
 		Pic
 		P1, P2, DF [CF, CIF, CI, C] D, LL (2 scales) 
Folded at 360.
 A, N [M, £, S/d, C] D, G Duplex
125 x 34 x 4 mm
 "Commerce." N, M have 365 division for dates. £, S/d = pound/ shilling/ pence. G is a set of conversion gauge marks.
 Pocket version of model P263.
149
 		1959-1962
 		Pic
 		LL/1. LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at π. 		L, K, A [B, TI, SI, C] D, LL0, LL/0 Duplex
125 x 34 x 4 mm 		"Pocket 259D" but actually closer to 259 with TI, SI instead of T, S, ST. Hemmi name on back of rule. Bare bamboo edges.
149A
 		1962-EOB
 		Pic
 		Same as 149 except celluloid veneer covers edges.
P149A
 		1976
 		Pic
 		LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at π.
 L, K, A [B, TI, SI, C] D, LL0, LL/0
 Duplex
125 x 36 x 4 mm
 All plastic. About 10 mm longer overall and 2 mm wider than bamboo 149A.

Models 150-300: Ten- and Twenty-Inch Duplex and Open Body Slide Rules
150

 		1925?-1932?
 Pic
 		DF [CF, CIF, C] D
Folded at π.

 		K, A [B, S, T, CI] D, L

 		Duplex
250 mm x 1 3/16 x ¼ in
 Hemmi's first duplex slide rule.  (But Hemmi called models 150, 152, 153 and 154 "Universal," not "duplex.") Copied from K&E 4088-3 whose size it exactly duplicates.
 Post 1458 (1931)
Lietz 3054L (before 1932)
1932?-MIOJ
 Pic
 		Duplex
250 mm x 1 5/8 x ¼ in
 Standard (1-5/8 inch) width. Replaced by model 250.
 Tamaya 4497 (1932)
Post 1458 (1932-WWII)
US Blue 1881 (--1937--)
H O 1765 (1935-MIOJ)
152
 		1925-48
 Pic
 		K, A [B, CI, C] D, T
 Θ, Rθ, P [Q, Q', C] LL3, LL2, LL1
Duplex
250 mm x 1 5/8 x ¼ in
 "Electrical Engineer's Universal" (Duplex). Often no model number. Some marked "US Pat 1459857." (Patent issued to O D Parsons in 1923 for P, Q scales.)
Tamaya 4498 (1932); Post 1459 (c1933-WWII); H-O 1766 (-1935-48-); US Blue 1889 (1930s) Lietz (1930s)
153
 		1931-EOB
 Pic
 		L, K, A [B, CI, C] D, T, Gθ
 Θ, Rθ, P, [Q, Q', C] LL3, LL2, LL1
 Duplex
250 mm x 1 5/8 x ¼ in
 "Electrical Engineer's Universal" (Duplex). Some (c1938) with stator screws on back of rule. US Patent 2079464, May 4, 1937.
 Post 1461 (c1933-WWII);
US Blue 1893 (1030s)
154
 		1925-69
 Pic
 		DF, P', P [Q, CF, CI, Sθo] A, D, K
Folded at π.
 Sχ, Tχ, Tθo [Th, Sh, Sh, C] D, L, χ
 Duplex
500 mm x 1¾ x ¼ in
 Electrical Engineer's Universal (Duplex) 20". Two cursors. Early production has scale letters eteched on cursor windows.
Tamaya 4499 (1932);
Post 1460 (c1933-WWII)
155
 		WWII-1951
 Pic
 		K, A, DF [CF, B, CI, C] D, L
Folded at √10.
 Sh1, Sh2, Th1 [TI2, TI1, SI1, C] D, DI
 Duplex
250 mm x 1 5/8 x ¼ in
 "General Engineering with Hyperbolic Scales. " Replaced by model 255.
157
 		WWII-1950
 Pic
 		K, A, DF [CF, B, CI, C] D, L
Folded at √10.
 LL/1, LL/2, LL/3 [TI2, TI1, SI1, C] LL3, LL2, LL1
Duplex
250 mm x 1 5/8 x ¼ in
 "General Engineering with Log-Log Scales."
159
 		1949-52
 Pic
 		T, DF [CF, CIF, CI, C] D, S, ST
Folded at π
 LL0, LL00, A [B, K, L, C] LL3, LL2, LL1
 Duplex
250 mm x 1 5/8 x ¼ in
 Made to specification of F Post Co. Replaced by model 259 ("Expert Mechanical Engineer") c1952.
 Post 1462H "POSTRIG"
(c1949 - 53)
160
 		1951
 		Pic
 		Nomogram1(α=0.05), χ2, A [B, CI, C] D, φ, ax
 P, F'1 [F'2, a'] A, χ2, ,Nomogram2(α=0.01)
 Duplex
250 mm x 72.5 mm
 "Inductive Statistics." Almost three inches wide! Stator with nomograms is about 46 mm wide. All-plastic cursor similar to Relay/Ricoh.
165
 		1953
 		Pic


"Statistical Sampling." No slide, just many short scales and a cursor.
190
 		1939-42
 		Pic
 		K, A [B, R2, R1, C] D, DI
 [SI2, SCI2, SI1, SCI1]
Bottom Edge: L
 Closed
250 x 40 x 11 mm
 "Precision Stadia." {3 hairlines: D: C, C}.
Left half of SCI1 scale is inverse cos2.
200
 		1936-68
 		Pic
 		D6, D5, D4 [C6, C5, C4, C3, C2, C1] D3, D2, D1
 DF6, DF5, DF4 [CF6, CF5, CF4, CF3, CF2, CF1] DF3, DF2, DF1
Scales divided at 6√10.
 Duplex
400 mm x 1¾ x ¼ in
 "Precision Duplex." (Originally known as "Ultra Accuracy.") Four digit precision. Scales are divided into six segments, each 400 mm long. Early production has scale labels in green on cursor. U S Patent 2235106A, March 18, 1941.
201
 		1967-69
 		Pic
 		L2.4, L1.3, A2.4, A1.3 [C4, C3, C2, C1] D1, D2, D3, D4
 K4, K3, K2, K1 [CF4, CF3, CF2, CF1] DF1, DF2, DF3, DF4
Scales divided at 4√10.
 Duplex
500 mm x 1¾ x ¼ in
 "Sold in Japan." Scales are divided into four segments each 500 mm long.  Early production has scale labels in green on cursor.
250
 		1950-EOB
 		Pic
 		DF [CF, CIF, CI, C] D, L
Folded at √10.
 K, A [B, TI2, TI1, SI] D, DI
 Duplex
250 mm x 1 5/8 x ¼ in
 "General Engineering and Business." Replaced models 150 and 2600. About a third have anodized black end brackets.
251

 		1951-58
 		Pic
 		L, DF [CF, CIF, CI, C] D, DI
Folded at π.
 K, A [B, T, S, ST, C] D, LL3, LL2, LL1
 Duplex
250 mm x 1 5/8 x ¼ in 		"Mechanical Engineer."
1958-EOB
 		Pic
 		L, DF [CF, CIF, CI, C] D, LL3, LL2, LL1 Folded at π.
 K, A [B, T, S, ST, C] D, DI
 H-O 1773
P253
1961-EOB
 		Pic
 		LL3, LL2, DF [CF, CIF, CI, C] D, L, LL1 Folded at √10.
 K, A [B, TI2, TI1, SI] D, DI.
TI divisions= 1/12 degree
 Duplex
250 x 41 x 5 mm 		Vectolog." Elaborate clamshell case. All-plastic version of model 264. ¥2.400 in catalog 6911.
 H-O 1774-00 (-1964);
Geotec 341-3130 (1964+)
P253 Special

 		1967
 		Pic
 		LL3, LL2, DF [CF, CIF, CI, C] D, L, LL1 Folded at √10.
 K, A [B, TI2, TI1, SI] D, DI
 Marked "P253 Special" and "Vectolog." Only difference from P253 is green CIF scale.
1965
 		Pic
 		LL3, LL2, DF [CF, CIF, CI, C] D, L, LL1 Folded at √10.
 K, A [B, TI2, TI1, SI] D, DI,√3V.
Marked "P253 Special" and "Vectolog."  Short additional scale on back marked "√3V" at left and and "volt" at right end.
254W

 		1963-68
 		Pic
 		LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at √10. 		K, A [B, TI, SI, C] D, DI, L Duplex
250 mm x 1¾ x ¼ in.


"High School Students". Basis for model 108 demo rule. Equal length stators.
1963-72
Pic
 		Traditional stators.
254 W-S






 		1970s
 		Pic
 		Same as 254W but folded at π.
 Same as 254W.
 Only difference from 254W is where front scales are folded.
 Only two specimens known. Date codes "RC" (March 1967) and "UB" (Feb 1970)
1969
 		Pic
 		Same as 254W. Folded at √10.
 		L, K, A [B, TI, SI, P] Q, Q', D, DI
 With P, Q, and Q' scales
 Date code "TC" = March 1969.
1970s
 		Pic
 		K, A, [SIN COS, COS2, TI, SI, C] D, DI, L
With stadia scales. Equal stators date = "OC" (Mar 1964); others = "UB" (Feb 1970) or no code.
1971
 		Pic
 		K, A [B, TI2, TI1, SI, C] D, DI, L
 "High School Students." Traditional stators. Hemmi name on back of rule.
1971
 		Pic
Same as 254W but folded at π.
 K, A [B, TI2, TI1, SI, C] D, DI, L
 Date code "VC" = March 1971
1970s
 		Pic
 		KI, K, AI, A [B, S, T, CI, C] D, LdB, P, DI
 		May set record for number of different inverse scales on one side of a rule.
1965
 		Pic
 		LL/1, LL/2, LL/3, DF [CF, CIF, ST, CI, C] D, LL3, LL2, LL1
Folded at π.
 KI, K, AI, A [B, S, T, CI, C] D, LdB, P, DI Equal length stators.
254WN
 		1972-EOB
 Pic
 		LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at √10.
 LL/0, K, A [B, TI2, TI1, SI, C] D, DI, L, LL0 "High School Students." Traditional stators. Hemmi name and model number on back of rule.
254 WN-S

 		1972
 Pic
 		Same as 254WN except folded at π.
1973
 Pic
 		Same as 254WN. Folded at √10.
 L, K, A, [B, TI2, TI1, SI, P] Q, Q', D, DI
255

 		1950-57
 		Pic
 		L, K, DF [CF, CIF, CI, C] D, χ, θ
Folded at π.
 Sh1, Sh2, Th, A [B, TI2, TI1, SI, C] D,LL3,LL2,LL1
 Duplex
250 mm x 1¾ x ¼ in
 		 "Expert Electrical Engineer." Replaced model 155.
1958-61
 Pic
 		L, K, DF [CF, CIF, CI, C] D, LL3, LL2, LL1     Folded at π.
 Sh1, Sh2, Th, A [B, TI2, TI1, SI, C] D, χ, θ
255D
 		1961-EOB
 Pic
 		L, K, DF [CF, CIF, CI, C] D, LL3, LL2, LL1     Folded at π.
 Sh1, Sh2, Th, A [B, TI2, TI1, SI, C] D, DI, χ, θ
256
 		1950-68
 Pic
 		L/dB, Neper, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at π.
 A, Ĺ [Ċ, SI, TI] D, l, F
 Duplex
250 mm x 1¾ x ¼ in
 Electrical Communications. Ĺ and Ċ scales are about half length.
257
 		1952-68 Pic
 		L, A, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at π.
 Ch A-M, Ch N-Z, M1 [M2, oF, oC, oK, F(t)] Kg/cm2, mm Hg, in. Hg Vac., tω
 Duplex
250 mm x 1¾ x ¼ in 		"Chemical Engineer."
Post 1491 (c1957-67);
H-O 1770 (-1958-)
257L
 		1971-EOB
 Pic
 		L, K, A, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at π.
 Ch A-M, Ch N-Z, M1 [M2, oF, oC, oK, LM] mm Hg, Kg/cm2, in. Hg Vac., tω
 "Chemical Engineer." Hemmi name on back of rule.
258
 		1951
 Pic
 		LL0, LL/0, K, DF [CF, CIF, CI, C] D, R1, R2, L
Folded at π.
 LL/1, LL/2, LL/3 [T T, SecT ST, Cos S, C] D, LL3, LL2, LL1
Duplex
250 mm x 1¾ x ¼ in
 VERSALOG Ia.  About 30 specimens marked "Hemmi 258" are known. All are also marked "THE FREDERICK POST CO. NO 1460" or "THE HUGHES OWENS CO. LIMITED NO. 1777."   Click here for a short history of model 258.
 Post 1460 Versalog (1951+);
H-O 1777 Versalog (1951+).
For information about Versalog models Ib and II see the second page of this Catalogue Raisonne.
259

 		1950-58
 Pic
 		L, K, DF [CF, CIF, CI, C] D, LL0, LL/0   
Folded at π.
 LL/1, LL/2, LL/3, A [B, T, S, ST, C] D, LL3, LL2, LL1
 Duplex
250 mm x 1¾ x ¼ in

"Expert Mechanical Engineer."  Replaces model 159.
1958-63
 Pic
 		LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1       Folded at π
 L, K, A [B, T, S, ST, C] D, LL0, LL/0
 "Expert Mechanical Engineer."  Hemmi name moved to back of rule.
259D
 		1953-EOB
 Pic
 		LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1      Folded at π
 L, K, A [B, T, S, ST, C] D, DI, LL0, LL/0
259D-S
 		1970s
 Pic
 		LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1      Folded at π.
 LL0, LL/0, K, A [B, T, S, ST, C] D, √1, √2, L

260
 1964-EOB
 Pic
 		LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1     Folded at π.
 LL/0, LL0, K, A [B, T, S, ST, C] D, DI, P, L
 Duplex
250 mm x 1¾ x ¼ in
 "Advanced Engineer."  {3 hairlines: A: C2, hp-C2}  Some rules c1970 have brand and model on bottom edge.  Some marked UNIVERSITY on bottom edge.  ¥4,800 in catalog 6911.
260 Demo
 		1964
 Pic
 		LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1     Folded at π. LL/0, LL0, K, A [B, T, S, ST, C] D, DI, P, L
 Duplex
1500 mm
x _
 Painted wood classroom demonstration  rule.  Cursor is single wire.
P261
 		1965-EOB
 Pic
 		LL01, LL02, LL03, DF [CF, CIF, CI, C] D, LL3, LL2, LL1
Folded at π. 		T, ST, K, A [B, BI, CI, C] D, L, P, S Duplex
250 x 46 x 5 mm
 "Advanced Engineer" (Darmstadt).  Stators white or pale blue.  {4 hairlines on back of cursor. A: C2, hp-C2, D: C}
T-P 1420 (c1971 only)
T-P 44CB-200 (1972+)
Geotec 341-3660
P262 1965-EOB
 Pic
 		LL01, LL02, LL03, DF [CF, CIF, CI, C] D, LL3, LL2, LL1     Folded at π.
 K, A, R1, R2 [T2, T1, ST, S, C] D, L, LL00, LL0
 Duplex
250 x 46 x 5 mm
 "Advanced Engineer" (Rietz).
 T-P 1422 (c1971 only),
T-P 44CB-220 (1972+)
P263
 		1964-69 Pic
 		P1, P2, DF [CF, CIF, CI, C] D, LL, LL    Folded at 360. A, N [M, £, S/d, C] D, G
Duplex
250 x 41
x 5 mm
 "Commerce."  N, M have 365 divisions for dates.  £,S/d = pound, shilling/pence.   G is a set of conversion gauge marks Geotec 341-3155 (1967+)
Hemmi 143 is pocket version.
264
 		1968-EOB
 Pic
 		LL3, LL2, DF [CF, CIF, CI, C] D, L, LL1      
Folded at √10
 K, A [B, TI2, TI1, SI] D, DI.    
Duplex
250 mm x 15/8 x ¼ in 		Bamboo version of model P253, Vectolog.
264-S
 		1969
 Pic
 		K, A [B, TI, SI, P] Q, D, DI. 
P & Q scales, Single TI scale.
264-M
Pic
 		K, A [B, TI2, TI1, SI] D, DI.   
A mis-marked model 264?  Only known specimen was sold on Yahoo Japan, June 2018.  Photo shows factory marking  "264-M."  
264-S
 		1970s
 		Pic
 		LL3, LL2, DF [CF, CIF, CI, C] D, LdB, LL1    Folded at √10.
 K, A [B, TI2, TI1, SI]  D, DI, χ, θ


P265
 		1968-72
 Pic
 		P1, P2, DF [CF, CIF, CI, C]  D, LL2, LL1    Folded at 360
 A, D [G,  0-24, N]  M, 0-24
 Duplex
250 x 46
x 4 mm
 "Business."  N, M have 365 divisions for dates.   G is a set of conversion gauge marks.  Instructions & scale labels in Japanese.
266
 		1961-EOB
 Pic
 		(LL/3 and LL/1), LL/2, LL2, A [B, BI, CI, C] D, dBL, S, T
 XL, XC, F, (τ1 and P),  [(τ2 and Q), L, C, Cz] L, Z, fo
 Duplex
250 mm 
x 1¾ x ¼ in
 "Electronics."  Announced in 1961 but not in Hemmi catalogs until 1966.  Early specimens (1962) marked "Developed by SONY."  LL/3, LL/1, τ1, τ2, P, Q are partial length scales.  Also sold as Geotec 341-3550 (1966+) 
P267
 		1971-EOB
 Pic
 		³√-3,  ³√-2, ³√-1, DF [CF, CIF, CI, C]  D, √-1, √-2, δ(unif.)
Folded at √10
 4√-4, 4√-3, 4√-2, 4√-1 [λδ(conc),  λδ(Trape),  λM,  P] Q, L, T, S
 Duplex
250 x 46 x 5 mm 		"Structural Design."
269
 		1965-EOB
 Pic
 		L, F, K, A [B, K', CI, C] D, LL3, LL2, LL1
 CL, SL, M, TL [R, ST, T, S, C] D, DI, SinCos1, SinCos2
 Duplex
250 mm x 1¾ x ¼ in
 "Civil Engineer."
P270
 1971-EOB
 Pic
 		J, J [T(ºK), Q(m³/s), Q(m³/s)]  Hm(m), Q(m³/s), Ht(m)
 X, X, Cz, Cmax(PPM)  [He(m), Cy, CI, C] D, A, L
 Duplex
250 x 46 x 5 mm
 "Pollution A."  (air quality analysis)  19 scales in black, red and blue.
P271
 		1974
 Pic
 		x,xs(g/kgDA), (ice),  Tφ,tφ(ºC) [hw,hs(mmhg), CI, C] D, v, va(m3/kgDA), t(ºC), t(ºF)
 [t(ºC)(ice), t'2.5,  t(ºC)]
 Open
250 x 46 x 5 mm 		Moist air.  There are 13 scales--most with complicated labels.
274
 		1973-EOB Pic
 		L, DF [CF, CIF, CI, C]  D, LL3, LL2, LL1
Folded at √10 		K, A [B, TI2, TI1, SI, C]  D, DI
 Duplex
250 mm x 1¾ x ¼ in 		Late model general engineering rule with scales folded at √10 and trig scales inverted.  Likely sold only in Japan.
274-S

 		Pic
 		K, A [B, TI2, TI1, SI, C]  D, DI, dB
NA
 		dB, K, A [B, TI2, TI1, SI, C] D, DI, χ, ϴ
275

 		1950-58
 Pic
 		L, K, DF [CF, CIF, CI, C] D, χ, θ   
Folded at π.
 Sh1, Sh2, Th, A [B, TI2, TI1, SI, C] D, LL3, LL2, LL1
 Duplex
500 mm x 1¾ x ¼ in 		20-inch Version of Model 255.
1958-63
 Pic
 		L, K, DF [CF, CIF, CI, C] D, LL3, LL2, LL1      Folded at π.
 Sh1, Sh2, Th, A [B, TI2, TI1, SI, C]  D, χ, θ
 20-inch Version of Model 255. Some with green scale labels on cursor.
275D
 		1963-69
 Pic
 		L, K, DF [CF, CIF, CI, C] D, LL3, LL2, LL1    Folded at π.
 Sh1, Sh2, Th, A [B, TI2, TI1, SI, C]  D, DI, χ, θ
 20-inch Version of Model 255D. Some with green scale labels on cursor.
279

 		1950-58
 Pic L, K, DF [CF, CIF, CI, C] D, LL0, LL/0        Folded at π.
 LL/1, LL/2, LL/3, A [B, T, S, ST, C] D, LL3, LL2, LL1
 Duplex
500 mm x 1¾ x ¼ in 		20-inch Version of Model 259.  Some with green scale labels on cursor.
1958-63
 Pic
 		LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL1    Folded at π.
 L, K, A [B, T, S, ST, C] D, LL0, LL/0
279D
 		1963-69
 Pic
 		LL/1, LL/2, LL/3, DF [CF, CIF, CI, C] D, LL3, LL2, LL     Folded at π.
 L, K, A [B, T, S, ST, C] D, DI, LL0, LL/0
 20-inch Version of Model 259D. Some with green scale labels on cursor.
P280
 		1959-72
 Pic
 		T, K, A [B, CI, C] D, L, S, ST
 [LL1, LL2, LL3]
 Open
250 x 46 x 4 mm
 "Beginners."
 T-P 1414 (c1971 only), 44BB-140 (1972+); Geo 341-3645; Ahrend P280.
280S
 		1976?
 Pic
 		L, K, A [B, CI, C] D, S, ST, T
 cm
[LL1, LL2, LL3]
inches
 Open
250 mm
 All plastic.  Marked "HEMMI, JAPAN, 280S" but probably made by D&P.  Only known specimen found in Thailand
 Ahrend P281;
Same as Aristo 0903 except back of Aristo slide is blank.
P281
 		1970-72
 Pic
 		T, K, A [B, CI, C] D, L, S, ST
 Blank
 Open
250 x 46 x 4 mm		 Rietz. T-P 1410 (c1971 only), 44BB-100 (1972+);
Geo 341-3640
P283
 		1970-71
 Pic
 		K, A, DF [CF CI, C] D, L, T, S
Folded at π.
 [LL1, LL2, LL3]
 Open
250 x 46 x 4 mm
 Beginners.
Ahrend P283.
Models 300-999: Specialty Slide Rules
300
 		WWII  Pic
 		G, E [F, CI, C] D, M
 [Blank]
 //Closed||
250 x 34 x 8.5 mm
 Decimal Calendar Rule.  G scale is folded at 365; E & F folded at 3.042 = 365/12.  M scale is set of gauge marks for Japanese weights & measures. Japanese language.
301
301A
 1954-69
 Pic
 		τ, ω [CI, f, P, C] D, A, db
 [θ, θd, g', g]
 //Closed||
250 x 34 x 11 mm
 Control Engineering.  Four cursors!  301A is 301 plus a transparent overlay.
 Post 1490 (1957-ca67)
305
 		1959-70
 Pic
 		TmV/S, ℓ1 [ℓ2, m, a] T, v
 [N, F, u]
 //Closed||
125x26 x _ mm
 Acoustic Design.  Patents 225936, 225937.
400
 		1959-68
 Pic
 		Y, A [B, CI, C] D, LL3, LL2, LL1
 Eß, R(AI), Dist, Dose Rate [S, Isotopes (4 scales)] Ev, Pb, Fe, Al
 Duplex
250 mm 
x 1¾ x ¼ in
 Radioisotope Engineering.
401
 		1966-69
 Pic
 		d, W [Nt, D, MI, M]  L
 τo, P [d, D, D, Na(δ)]  k(P), d
 Duplex
250 mm 
x 15/8 x ¼ in
 "Coiled Spring Rule."
P402
 		1966-69
 Pic
 		15 scales in black, red, blue and green -- all labeled in Japanese.  Only three scales are full length.  Scale arrangement and range of variables differs slightly between the two models. A, DF [CF, CIF, CI, C] LL (2 scales)
Folded at √10. 		Duplex
250 x 41 x 5 mm

 		"Tanabe Corporate Performance Analysis."  P402 for manufacturing businesses; P403 for wholesale and retail distributors.  Rule and instructions in Japanese. Click here for an illustrated explanation of models P402 and P403 by Atsushi Tomozawa.
P403
 		1966-69
 Pic
405
 		1950-68
 Pic
 		C2F, Al2O3 [Fe2O3, C2AF]  C2A, SO3, CaSO4
 C2S (A Scale), CaO [SiO2(for C3S), Fe2O3, SiO2(for C2S), SO3/Al2O3]  C3S, C2S (B Scale)
 Duplex
250 mm 
x 1¾ x ¼ in
 "Cement Composition."  Scale labels are chemical symbols, numbers subscripted.  No scales are logarithmic. Fe2O3 and SiO2(for C2S) are separate short scales on same line.  Accompanying Instruction Manual published by Portland Cement Assoc. Skokie, Ill, May 1959. 
410
 		1959-69
 Pic
 		G2, G1, F2, F1 [x, F1G1]  Z1+Z2, G', F'
 G2, G1, F2, F1 [x, CI, C]  D, A
 Duplex
250 mm 
x 1¾ x ¼ in
 "Involute of Gear Wheel."
451
 		1969
 Pic
 		Eight specialized scales.  Center scales are not full length.
 LL/3, LL/2, LL2, A [B, BI, CI, C]  D, dBL, S, T
 Duplex
250 mm
"Field Intensity."
There are bamboo and all-plastic versions of this rule; both are marked "451."  (Not "P451") 
P452
 		1968-72
(For Post)
 Pic
 		LL1, LL2, LL3, CR_DF [T_CF, CIF, %_CI, T_C] R_D, L, in, cm       Folded at π
 ST, 3n-2_K, 2n-1_A [B, BI, CI, C] D, P, S, T
 Duplex
250 x 46 x 4 mm
 "Business."  Some marked "System H. Kroon."  Yellow slide, green brackets.  (Post & T-P have blue slide & brackets)
 T-P 1426 (c1971 only), 44CB-260 (1972+)
500
 		1943
 NA

125 mm 
x _
 "For Airplane."  ¥8.50 in 1943 price list.  No other mention.
640S
 		1972
 Pic
 		K, DF [CF, CIF, CI, C] D, A, L    
Folded at √10.
 [STI, TI2, TI1, SI, CI]
//Closed||
250 x 45 x 9 mm
 Desk Rule.    Bamboo between thick plastic
641
 		1975
 Pic
 		K, A, DF [CF, CIF, B, CI, C] D, DI, L   Folded at √10
 [STI, TI2, TI1, SI, CI]
//Closed||
250 x 45 x 9 mm
 Desk Rule.   Bamboo between thick plastic.
642T
 		1973
 Pic
 		K, A [B, BI, CI, C] D, DI, L      
with over-range
 [T2, T1, ST, S]
 //Closed||
250 x 45
x 9 mm
 Desk version of 64T. Bamboo between thick plastic. 
{3 hairlines: D: C, C}.
 Ahrend 643T
651
 		1969
 Pic
 		K, A, DF [CF, CIF, B, CI, C] D, DI, L
Folded at √10.
 [TI2, TI1, STI, SI, C]
//Closed||
250 mm x 1½ x 7/16 in

Models 1xxx: Circular Slide Rules
1001
 		1971
 Pic
 		A, D, C, CI, L
 Blank
 Circular
80 mm
 Circular.
    Geotec 341-3910
1002
 		1971
 Pic
 		A, D [C, CI]
 Blank
 Circular
80 mm
 Circular.  Less elaborate than 1001.
2600 Series Rules Introduced in 1940 (February 11, 1940 was the 2600th Aniversary of the Founding of Japan) 
2600
 		1940-51
 Pic
 		DF [CF, CI, C] D, L
Folded at √10.
 K, A [B, TI2, TI1, SI1] D, DI
 Duplex
250 mm 
x 15/8 x ¼ in
 General Engineering and Business.

2634
 		1949-EOB
 Pic
 		K, DF [CF, CI, C] D, A
Folded at √10.
 [TI2, TI1, L, SI]
//Closed||
125 x 26
x 5 mm
 Pocket 2664.

P2634
Pic
 		K, DF [CF, CI, C] D, A
Folded at √10.
 [TI2, TI1, L, SI] ||Closed||
125 mm
x _

2640
 1949-68
 Pic
 ℓ, A [B, CI, C] D
 [S, K, T]
(S keyed to C/D)
 ||Closed||
200 x 28
x 8 mm
 Beginners Slide Rule for 50W.  Plastic cursor.
2641
Pic
 		DF [CF, CI, C] D, A
Folded at √10.
 Blank
 ||Closed||
200 x 28
x 8 mm
 Beginners Slide Rule for 45 (which, itself, was a beginner's rule).  Plastic cursor.
2645
 		WWII
 Pic
 		DF [CF, CI, C] D, A
Folded at √10.
 [TI, L, SI]
 Closed
200 x 28 x 8 mm
 Essentially identical to model 45 except CI scale is black.
Only one specimen known.
2662
 1966-69? Pic
 		K, A, DF [CF, CIF, CI, C] D, DI, L
Folded at √10.
 [B, TI, SI, C] //Closed||
250 x 34
x 11 mm
 Some with 13-0-13 cm scale on bottom edge. See Hemmi Catalogue Raisonne 2 for a slide projector version of this rule.
2664 WWII
 Pic
 		K, DF [CF, CI, C] D, A+L
Folded at √10. 		[TI1, TI2, SI2, SI1] ||Closed||
250 x 34
x 9 mm
 Wartime construction (bare vertical edges and back)  No model number on rule.  A+L scale is left half of A scale joined to right half of L scale.
MIOJ
 Pic
 		K, DF [CF, CI, C] D, A       Folded at √10.
 [TI2, TI1, L, SI1]
 //Closed||
250 x 34
x 11 mm 		Better quality construction.  Full length A scale; L scale replaces SI2. 
1949-58
 Pic
 		K, DF [CF, CI, C] D, A+L    Folded at √10.
 [TI1, TI2, SI2, SI1]
A+L scale is left half of A scale joined to right half of L scale.
2664S
 		1958-69
 Pic
 		K, DF [CF, CIF, CI, C] D, A Folded at √10.
 [TI2, TI1, L, SI]
//Closed||
250 x 34
x 11 mm
 Same as 2664 except 10 mm longer overall and green CIF scale added.
¥2,200 in catalog dated 6911
2664S-S
 		1967
 Pic
 		K, A, DF [CF, CIF, CI, C] D, DI
Folded at √10
 [TI2, TI1, L, SI]
//Closed||
250 x 34
x 11 mm
 Same as 2664S except DI scale added.
2670
 		MIOJ
 Pic
 		K, A [B, CI, C] D, L
 [S, S&T, T]
//Closed||
500 x 40
x 12 mm
 Long Rietz.  Short-lived replacement for model 70.  {3 hairlines: D: C, C}.
2690
 		1951-68
Pic
 		L, D [M1, M2, C] D, A
 [S, S&T, T]
//Closed||
250 x 34
x 11 mm
 Stadia.  {3 hairlines: D: C, C}.
2690A
 		1954-55
 NA
 		Same as 2690 "2690A" marked on case to distinguish model 2690 from proposed centesimal degree model 2690B.  Rules are marked just "2690."  
Odds and Ends
P3526
 		1970s?
 Pic
 		S, K, A [B, CI, C] D, L, T
 None
 ||Closed||
250 x 40
x 3 mm
 Beginner's all-plastic slide rule marked "HEMMI, Japan, NO P3526"  but manufactured by Hope Slide Rule Mfg Co, Tokyo.  Same as Hope model 51.  (The only known 'Hemmi' example was found in New Zealand.)








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