When do the pitching regulations officially begin?

The pitching regulations officially begin when the pitcher intentionally contacts the pitcher's plate. This action signifies that the pitcher is ready to engage with the batter and acknowledges the start of the pitching process. Once the pitcher has established this position, various rules concerning the delivery of pitches, the time allowed between pitches, and interactions with the batter come into effect.

Understanding this clarification is crucial, as it directly affects how the game is played and managed by umpires and players alike. Other options, such as the batter stepping into the batter's box or the catcher giving a sign, do not initiate the official pitching regulations. These actions may precede the pitch but do not mark the official start of the pitching process as defined by the rules. Umpires do play a role in overseeing these regulations, but the action of the pitcher contacting the pitcher's plate is the definitive moment when the regulations are activated.