In the Meiji era (19th century), four samurai challenged each other to try and cut a war helmet in the presence of the Emperor. At first glance, the chances of splitting a heavy helmet, built under the same principles as the sword, were practically null. However, one of them managed to split the helmet, the resulting gash measuring 10cm in length and 2 cm in depth!
No modern blade, mechanically machined could have cut through such a helmet. This is the reason why, in ancient Japan, large blades were much sought after. Such examples, in addition to the beauty of these swords and their mountings, explain why still today, some of these blades are priceless.

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