When you chose your shinai , you think about not only ① length
and weight but also ② balance and ③ types
Meaning of 37,38,39 numbers ?
1 shaku = 30.3cm
1 foot = 30.48cm
1 sun = 3.03cm
1 inch = 2.54cm (this is a bit different but not a super huge difference).
The old Japanese system of measurement was based on the “Shaku” and “Sun”
All manner of objects were measured with this system, including swords,
kendo armor and shinai, and clothing.
1 shaku = 10 sun = 100 bu = 1000 rin
To convert centimeters to shaku/sun, divide your measurement by 30.3.
For example 120 cm divided by 30.3 equals 3.9 , or 3 shaku, 9 sun
(a “39” shinai.)
Weight and Balance ?
Dobari Shinai have a large bulge in the bamboo near the handle.
Making the Shinai tip feel lighter.
Koto/chokuto Shinai are straighter, with the tip feeling heavier.
Meaning of Grade 'A','AA','AAA' ?
One bamboo can be divided into 6 to 8 staves.
"AAA" shinai adopts 4 staves from the same bamboo, which not only makes
the Shinai look more complete and nice, but decreases the possible friction
among the 4 Take because they all grew together before, thus it enhances the Shinai
durability. Theoretically, "AAA" is the highest standard among all Shinai except
hand made Madake Shinai. "AA" means that the Shinai adopts 2 staves of one bamboo
and the other two are from other bamboos. "A" stands for the Shinai which is made of
staves from different bamboos.
Follow to Regulation of shinai size chart