Tanren bō

A nihongo|tanren bō|鍛錬棒 is a bat used in aikido for strength and suburi training. Despite being only 3 feet overall, with 10 inches for handle, the "blade" is a large lump of rectangular wood, with its cross-section being a square with dimension of three square inches, and have overall weight of 4 to 7 lbs.

By designating one corner as edge, an aikidoka can use it as an even heavier suburitō, practice suburi, kata, hasuji (edge-angle) and tomei, and learn the bounce-back of the sword by practicing against tanrenuchi, now typically a tyre stood upright on a concrete base.

As it is designed toward aikido and strength training, specifically for getting used to the weight of a heavy-handled object, it does not resembles a sword in shape, length, or mass. Thus, unlike suburito, it is less effective of learning the katana's cut, and is not suited to contact with other swords.

References

*http://ejmas.com/pt/ptart_taylor_1200.htm