Here are the explanations of the old "Urame" (back measurements)

Front measurements
  On the front surface of the Japanese Framing Square, on the Naga-te and Tsuma-te measuring arms, measurements of 1mm are engraved onto the measure. To make reading easier, every 5cms the measuring number is printed in bold.
(the archaic Japanese measuring system of "shaku" may also be present)

Back measurements
  Measurements of the Japanese "Kakume", "Marume", "Kaeshime" and "Gyakume" are represented.

"Kakume" is a unique measurement of a Japanese square which measures out the square root of 2.
√2 times (1.4142135623...times)

"Marume" is the measurement that divides the front measurement by Pi (3.14...)

"Kaeshime" a symbol printed on the measure, which points out important measurements on the front surface of the framing square. Printed so one does not have to flip the measure around.

"Gyakume" small measurements printed on the edge so one can measure the depth of small cracks and chiseled areas.

1 sun	good luck
2 sun	bad luck
3 sun	bad luck
4 sun	good luck
5 sun	good luck
6 sun	bad luck
7 sun	bad luck
8 sun	good luck

  On the back surface of the framing square, is the measurements of 1 "shaku" (approximately a foot, 30.3 cm or 11.93 inches, [average length between nodes on bamboo]) and 8 "sun" (3.03 cm). The 8sun measures the length of objects from the ancient times. The length of a statue of Buddha, a sword, gate door, window, etc. Certain measurements were considered to be lucky "kichi" or unlucky "kyo" and there are records of fortunes being told with such measurements.

It is said that Osaka castle was actually built with the measurements of Kikyo-jaku in mind.

  Modern Japanese framing squares are mostly measured in meters (metres) these days with the old school "shaku" measurements on the back surface.

 In the past, Japanese framing squares had to be quite flexible as they were constantly bent, but had to avoid warping so measurements would always remain concrete. Hence steel was the recommended material to be used. But in the past, brass was considered to be more useful than steel due to its resistence towards rust compared to steel and as measurements written on brass was easier to read than steel.

  Brass framing squares were actually enforced with steel "hagane" at the right angles to avoid warping.

  Nowadays, stainless steel framing squares are used for its strength, resistance towards warping and rusting.

1. Draw line.
2. Draw perpendicular line.
3. Width of the measure is 15.1mm. Draw parallel lines to the edge.
4. Bend the "Naga-te" (Long arm) to draw line.
5. Check for bumps and bevels on the target material.
6. Use two squares to check to see if the material is warped.

  Hold with your right hand and bend as represented on the right image.

  As the image shows, if the diameter of the lumber is 25cm, ("kakume") one can achieve a block of wood where the sides are 25cms.

  If the diameter of the lumber is 70cm on the "Marume" measurements, the circumference of the lumber is 70cm.

  If for example, one is to divide a small piece of board into 6 equal parts. Measure out 30cms so that 0cm matches side (AC) and 30cm matches side (BD)(fig.A). Then mark down every 5cms, and align square as in fig. B to get 6 equal parts.

  Use the frontside measurements. With "A" cm sides, one can measure out an octagon using the following diagram.

  With an Japanese framing square, one can easily draw a;

• Equilateral triangle
• Pentagon
• Hexagon
• Heptagon

fig. 1 follows a 3:4:5 ratio format.
fig. 2 is by using the "Kakume" measures.
  Triangle with sides that equal to 3:4:5 are considered to be the most common form of measurement for large Japanese framing squares.

"Koubai" - slope or incline.
"Hirakoubai" - Slope where the vertical measure is indicated in "sun" against the hypotenuse, and the hypotenuse itself is measured as one "shaku."