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Flying circus of physics

Japanese samurai horo: silk cloth versus arrows

Thursday, October 01, 2015

Japanese samurai horo: silk cloth versus arrows
Jearl Walker
October 2015  When a Japanese samurai leader rode his horse into battle, he wore a horo on his back. This was a large, light-weight cloth that was mounted on a light-weight frame of bamboo or some other material. When the horse galloped, the influx of air would fill the horo, causing it to billow behind the warrior just as air can fill a sail on a sailing ship.

The function of a horo has long been debated: Did it act merely as a colorful part of the uniform, designating the allegiance of a samurai? Or did it have some protective measure against arrows shot at the samurai’s back? Could it, in fact, snag an arrow so that the arrow lost most or all of its kinetic energy before the tip reached the back of the warrior? That would be especially useful if the warrior was being chased by an enemy.

Here is a video showing experiments where arrows were shot into billowing cloth. The first experiments are done with target positioned behind the cloth, which was filled with air by an electric fan. The last experiments are done by a person riding on a horse while actually being shot at by a person on a trailing horse.

The result: A horo is not perfect protection against arrows, especially against large, sharp arrows, but it can offer some protection.

The idea for this story came from Martin Schumacher of Germany.

A related FCP story is about Alexander the Great, whose body armor was a woven linen. To see the story, go to

and then scroll down to item 1.130.

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