Craft #01


けん玉と精度 Kendamas and accuracy

MUGEN MUSOUのけん玉を語るうえで欠かせないことが、木工技術の精度です。難易度の高い技を決め、美しい仕上がりのけん玉をつくるには木工の精度はかかすことができません。


そのためMUGEN MUSOUでは±0.2mmという極めて高い基準を自ら設定し、その基準をクリアしたものだけを製品として販売するようにしています。

Mugen musou’s Kendamas cannot be talked about without mentioning their accuracy. Accuracy is important for Kendamas to improve the success rate of their tricks and to make them beautiful.

Accuracy is especially significant in creating a good balance. The balance of a Kendama affects its success or failure, especially in tricks like lunar. However, it is difficult to make all the Kendamas perfectly balanced, because even a small difference in shaving can easily affect their balance.

For that reason, Mugen musou sets itself an extremely high standard of ± 0.2 mm and sells only products that have passed this criteria.

木工における精度 Accuracy for Woodwork


Shaving wood may sound easy to do, but maintaining a high level of accuracy is extremely hard work. The biggest reason for this is because it’s a natural material. You may have seen a wooden table that has warped - this happens because the natural wood shrinks depending on the temperature and humidity. Every single piece of wood has its own hardness and personality. So, that is why the standard of ± 0.2mm is hard to achieve with woodwork.




With current technology, there is a way to shave the wood using a machine called Computer Numeric Control (CNC). However, it is difficult to achieve Mugen musou’s standard of ± 0.2mm with this machine. The reason is because even among pieces of the same kind of wood, the hardness and density differ depending on 1) whether it is from the inside or outside of the tree, 2) whether it grew closer to the roots or the top of the tree, and 3) the weather, temperature, and humidity of the place in which it grew.

So, what happens if we shave those all of this wood in the same way by machine? Even though the size will be the same on the data, the actual finish will show the difference. Some pieces may become scuffed on the surface and some may become smooth on the surface. Also, the blade used for shaving wears down while using it, which can also cause differences in the finish.

After the initial shaving, sandpaper is used to further reduce the surface down to 0.1 to 0.5mm. If each product has been produced using the above process, scuffed surfaces may end up being polished too much, and smoother surfaces may end up being polished too softly. Again, in the end, it affects the accuracy of the final finish.


Therefore, the craftsmen’s skill and experience are significant to achieving the standard of ± 0.2mm. Mugen musou’s craftsmen change their ways of shaving and polishing by judging 1) the condition of the wood, 2) the sound of the shaving, and 3) the condition of the knife and sandpaper.

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