Overview
A balk is called when a pitcher commits an illegal motion during the delivery. With runners on base, all runners advance one base. The same motion with the bases empty is treated as an illegal pitch, and a ball is added to the count. Common balk violations include stopping mid-delivery, faking a throw to first base without stepping off the rubber, failing to come to a complete stop in the set position, and insufficient stride when throwing to a base while touching the pitching plate. Across NPB only about 20 to 30 balks are called in a full season, judging by the five seasons from 2021 through 2025, yet the call still leaves room for umpire judgment and the standard can look inconsistent. Ahead of the 2018 season NPB announced that it would ease the criteria for balks caused by an incomplete stop in the set position, a change decided by the umpires after managers argued at that January's meeting of the 12 clubs that the calls had become too strict. Pitchers with deceptive pickoff moves work close to that boundary, and on the official career lists the leaders are Takenori Emoto with 24 and Tetsuya Yoneda with 23; long careers pile the total up, but pitchers who spent only a few seasons in Japan also reach the upper ranks. A balk-induced advance in a close late-inning situation can directly affect the outcome, making this seemingly minor rule a potentially decisive factor in games.