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Mysterious Scale on Right Angle Square?

Sarah Szabo

後輩
9 Feb 2018
18
2
18
My host dad gave me a carpentry square to bring back home with me (Which was really nice since I like carpentry), but one side of it has a number scale that I'm not familiar with.

I also bought a right angle square (Which I have no idea how to say in 日本語 BTW), the translate translation doesn't appear to be accurate.
My dad said the L square is called a 差し金.

It has a different scale than inches or centimeters as shown by the measuring tapes (Larger scale is a Dewalt imperial, Smaller scale is in centimeters), and the steel 差し金 and right angle square are in something different.
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As you can see, they also have special markings in Kanji as well.

My host dad told me that it was an old number scale (He said it might have had something to do with making shrines). Both squares are made by シンワ, but I don't think they made the scale.

Thanks!
 
Best I could find without knowing some of the kanji is ホゾ穴測定目盛 is horizontal hole measurement scale. Maybe there's a particular scale used for the distance between holes for construction there. 角目 seems to be another way to refer to 差し金. Not sure if this helps as all but if not maybe a native speaker will see this and be able to assist further.
 
Best I could find without knowing some of the kanji is ホゾ穴測定目盛 is horizontal hole measurement scale. Maybe there's a particular scale used for the distance between holes for construction there. 角目 seems to be another way to refer to 差し金. Not sure if this helps as all but if not maybe a native speaker will see this and be able to assist further.

I think that this website explains it, but I can't make heads or tails of it. Translating the webpage helps somewhat, but it's... cryptic: 差し金の使い方とは?丸目・角目の特徴と角度の測り方を解説! | 工具男子新聞
 
I looked on Shinwa's website, and they explained 角目 (kakume) as being the value on the other side of the ruler multiplied by the square root of 2 (1.41...). It is used to measure the diameter of a log. It will tell you what size square beam you can make from a log. A log with the diameter of 4 kakume will allow you to make a 4cm x 4cm square beam, assuming the units on the opposite side are centimeters. At least, that's what I think this says (nervous-faced smiley).

曲尺の目盛に角目、丸目がありますが、どういった目盛ですか。 - シンワ測定株式会社
 
ホゾ穴 (Hozo-ana) is the depth of a groove in a tongue-and-groove construction (particularly as relates to Japanese woodworking).
The other markings (離・義・官・etc) look like terms used to describe lucky or auspicious measurements (or, conversely, unlucky measurements). It looks like its a kind of geomancy or almost like feng-sui. For example, a gate fence should have a certain measurement otherwise it will be unlucky, or a pillar of a house should have a certain height and width in order to bring maximum luck to the house.
 
The company's name シンワ and the model number 10590 shows that what you got is 曲尺平ぴた シルバー 1尺5寸裏面角目.

You can see the English version on the page 15 in their web catalog, but the Japanese version has more detailed information.
(EDIT: I found that there are English explanations how to use special scales such like square scale or circle scale of sashigane on the page 25.)
Shinwa Rules Co., Ltd. GENERAL CATALOG 2018 :: ActiBook

曲尺 かねじゃく: another name of 差し金
シルバー: silver color
尺 しゃく: a Japanese unit of length, 10/33m
寸 すん: a Japanese unit of length, 1/10尺 (= 1/33m)
裏面 うらめん: the back side
角目 かどめ: square scale*

Thus, your sashigane is a Japanese unit version whose long branch's length is 1 shaku 5 sun(= 15/33m), and the square scale* is used in the back side.

表目盛 長枝:外目盛 尺5 内目盛 1尺
短枝:外目盛 7.5寸 内目盛 7寸
front side
long branch
outside: 1 shaku 5 sun
inside: 1 shaku

short branch
outside: 7.5 sun
inside: 7 sun

裏目盛 長枝:外目盛 角目 内目盛 吉凶・ホゾ(= ホゾ穴測定目盛)
短枝:外目盛 7.5寸 内目盛 丸目
back side
long branch
outside: square scale*
inside: lucky/unlucky scale, scale to measure the depth of a hole

short branch
outside: 7.5 sun
inside: circle scale**

*
Square Scale is "√2× the unit", i.e., 1 SS sun is approximately 1.41 sun. You can get the length of a diagonal line of a right square by measuring with this scale, other than the usage Majestic-san wrote.

**
Circle Scale is "1/π × the unit", i.e., 1 CS sun is approximately 0.32 sun. You can get the length of the circumference of a circle by measuring a diameter of the circle with this scale.

As for lucky/unlucky scale, each kanji 財, 病, 離, 義, 官, 劫, 害 and 吉 are put every 1/8 to the whole length. Seems like 財, 義, 官 and 吉 are for lucky, and the rest represents unlucky.

About the monkey 申, this is one of the twelve signs of the Chinese zodiac. Carpenters often use the one of the sign of their birth year.

You can see how to use sashigane in various ways in the following page.
(all in Japanese)


The right angle square is called スコヤ in Japanese. Wikipedia says that スコヤ is a corrupted form of the English word "square".

スコヤの語源は直角を意味する英語のsquare(スクエア、スクウェア)が訛ったものとされている。
 
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