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Nihonto Performance Lessens in Cold Weather

A Test by Omura Kunitaro
Translated material provided by

The publisher of Token Kogei magazine, Omura Kunitaro, coordinated a sword-breaking test with the assistant of Sakasaki Shinzou on Feb.11th, 1937 at the Nagoya Shinbunsha. During that time, the Japanese Army had been fighting in the extreme cold weather conditions of Manchuria. The purpose of this experiment was to test the durability of Japanese swords in this type of environment.

Omura Kunitaro was from Hiroshima. He spent a year in America after graduating from high school. Later, he developed vast interest in Nihonto related topics and learned sword polishing from the Fujishiro family. Omura Kunitaro became quite active in the sword world and published a monthly magazine called Token Kogei (the craft of swords) from 1934 to 1944. Sakasaki Sinzou was a contemporary sword smith. He was recorded on the gendai smith list published in 1942 by Kurihara Hikosaburo Akihide.

The testing blades were first conditioned to -60 ° C. Then they were placed on two small pillows for testing one at a time. A blade stored at normal room temperature was used to cut the testing blade placed on the pillows. The Yagyu Ryu swordsman, Kurimoto Shinzo, performed the test cuts. The results were as follows:
1) Norimitsu katana, ni-ji mei, Sue Bizen kazu uchi mono, bent upon a single cut. (This blade was the first tested and it was at normal room temperature )

2) Norimitsu katana, (Blade from test 1) After it was conditioned to -60 ° C, it was broken when struck.

3) Tadamitsu katana, Bishu Osafune Tadamitsu, Meiou 3rd year 2 month day, a well made sword with horimono, conditioned under -60 ° C, broken when struck.

4) Masaiye tanto signed Mihara ju Masaiye, era Choroku , conditioned under -60 ° C, bent and large ha-gire when struck.

5) Yamato-mono katana, mumei, Oei period, conditioned under -60 ° C, bent and large ha-gire when struck.

6) Muramasa tanto, mumei, 2nd generation, conditioned under -60 ° C, bent when struck.

7) Mino-mono wakizashi, mumei, Oei period, conditioned under -60 ° C, bent when struck.

8) Morimasa wakizashi, Bishu Osafune Morimasa, Oei 21 year 2 month day, conditioned under -60 ° C, big and deep shinae occurred on the ji when struck.

9) Mihara-mono katana, mumei, Tenbun period, conditioned under -10 ° C bent with three large ha-gire when struck. One of these ha-gire caused the blade to break.

10) Sue Shimada-mono tanto, mumei, conditioned under -60 ° C broken when struck.

11) Shinto Seki mono, mumei, heavy and thick tanto, conditioned under -15 ° C broken, one big mune gire and three ha-gire when struck.

12) Signed and dated gendai tanto, by Toukoto in mid autumn of Showa 11, modern steel alloy of Tungsten and Molybdenum, conditioned under -60 ° C bent when struck.

The above sword breaking tests are evidence that Nihonto do bend or break under extremely low temperatures. The cutting ability should be the first consideration for a Nihonto. Its beautiful appearance comes in second. A true Nihonto should fulfill the first requirement of being a weapon and that is to cut well. The beautiful appearance is only secondary. Art-sword theorists have the priority of this all wrong.

Nagoya Shinbun, Nagoya Shinbunsha, February, Showa 12
Shumi no Token Kenmasube, Omura Kunitaro, May, Showa 8
Nihonto no Kantei to Kenma, Omura Kunitaro and Fukunaga Suiken, June 1st, Showa 50.