As a result, when the Japanese armed forces adopted traditional Japanese swords (in place of the Western-style sabers they used initially) front-line soldiers experienced high rates of failure. These failures were documented by NARUSE Kanji (1888--1948). Naruse was a master of several traditional martial arts who, upon being drafted into the Japanese army during the Sino-Japanese war (ca. 1894), became employed as a sword repairman. As a result of what he saw on the battlefield Naruse became a lifelong advocate for changing the design of Japanese swords. He wrote three books which recently have attracted the attention of a new generation of readers: Tatakau nihonto (1940, Japanese swords in battle), Jissen todan (1941, Discussion of practical swords), Rinsen tojutsu (1944, Battlefield swordsmanship).
During one nine-month period Naruse kept detailed notes. During that period he repaired more than 2,000 swords. The sword ranged from all historical periods: 25% were Koto, 60% were Shinto or Shin Shinto, and 15% were Gendaito. Only 30% had been damaged in battle. In other words, most of them (70%) had been damaged in training or through mishandling. The types of damage they suffered is very instructive. Scabbards required the least attention: about 10% of scabbards had been broken or split --- a problem primarily caused by the stress of incorrect unsheathing or re-sheathing the swords. Blades, of course, were a problem, but not the most numerous problem. About 30% of the swords suffered bent or broken blades. For the most part, these were the swords that had actually been used in battle. (Although at least one sword was broken when a horse stepped on it.) Naruse was shocked at the high rate of blade failures. The main problem, however, was not the blades. It was the sword handles. A full 60% of the swords needed to be repaired because their handles had broken. Worse, Naruse reported that almost every sword he examined need to have the handle's mekugi (retaining pins) replaced. Even without severe use, the mekugi quickly wore out or became damaged.