How good were the Japanese torpedoes?

At the beginning of the war, the Japanese torpedoes were probably the best of any navy. The Type 93 torpedoes, fired from destroyers and cruisers, were particularly effective.“During the course of the war, 22 Allied warships were sunk after Type 93 hits: 10 cruisers, 11 destroyers, and one fleet aircraft carrier [the USS Hornet]. Thirteen of these had been fatally hit solely by the Type 93, with the rest succumbing to a combination of bombs, gunfire, and torpedoes.”

https://en.wikipedia.org/wiki/Type93torpedo

Submarines did not use the Type 93. However, the Type 95 submarine torpedo had many of the same strengths as the Type 93.