What Are the Side Numbers on a Mastermind Board? Turn Counters

They are turn counters (1–10 or 1–12 depending on edition).

• Each row = one guess by the Codebreaker.
• The printed number simply shows which attempt you're on.
• No hidden mechanic—purely for tracking progress toward the limit (usually 10–12 guesses).

Some travel versions use pegs in a separate track instead of printed numbers.