Japanese submarine torpedo kills in war and exercises

When did a Japanese submarine last achieve a torpedo kill?

Probably during World War II in combat, although Japanese submarines have also achieved torpedo successes in later exercises; no exact last case is identified.

A wartime torpedo kill is distinguished from sinking a target during an exercise. World War II is offered tentatively as the last wartime case, with the observation that Japan had no operational submarines in the Korean War. Later exercise successes are acknowledged, but no submarine, target, or exact date is identified.