The suburito - heavy wooden sword
In Japan, the word suburi refers to any warm up swinging whether it be for baseball, golf, tennis etc. but many of us think of it in terms of a solo practice where the practitioner swings a sword in open air.
And most of us are familiar with the large wooden sword, the suburito 素振刀, designed specifically for this reason.
Often, when outsiders come into the Kingfisher shop and see the suburito for the the first time, its big, club-like appearance seems Neanderthal in character. I remember the first time my fellow aikidoka and I saw one in the dojo years ago and we all started laughing. And like many things in the martial arts, it elicits all sorts of misconceptions.
But as with many things, its appearance is misleading. The suburito does a lot more than mimic the weight of a live blade. While it may weigh as much as a shinken, its balance is disproportionately more forward, and this is the key to its utility as a training tool.
It's useful for warm up and joint flexibiliy—most certainly. But since effective sword work does not rely on strength, the suburito is not intended to build muscle in the sense a weight lifter might use heavy weights. It does, however, expose weaknesses—and this is its essence.
After many cuts, the arm muscles tire. So much so that strikes cannot be performed with the inferior muscles of the shoulders and upper body alone. After exhaustion, the power of the central core and hips are drawn in by necessity. The cuts cannot be executed without learning to use the entire body. And this is the unseen value of the suburito.