How Basic Signs Work
Catchers deliver signs for approximately 130-150 pitches per game. The basic system uses finger count to designate pitch type - one finger for fastball, two for curveball. However, modern NPB pitchers carry 5-7 pitch types, exceeding simple finger-count capacity. Combination signs using multiple sign exchanges have become standard - for example, only the second of three exchanges being valid. When runners reach second base, sign-stealing risk increases, triggering more complex sign systems. Since around 2018, electronic sign transmission devices have been discussed, and MLB adopted PitchCom across all teams in 2024. NPB continues debating similar technology adoption as the traditional sign system faces modernization pressure.
Find books about catcher signs on Amazon
The History of Sign Stealing and Countermeasures
Sign stealing has existed throughout baseball history. Second-base runners reading signs and relaying pitch type or location to batters is prohibited by rules but difficult to completely prevent. Sign-stealing allegations have surfaced multiple times in NPB. Countermeasures include catchers changing sign keys every inning and pitchers verbally confirming with catchers on the mound. Catchers also commonly hide their hands behind their thighs when giving signs to prevent bench-level theft. MLB's 2017 Houston Astros sign-stealing scandal became a major issue, leading to stricter penalties for electronic sign stealing. NPB developed similar concerns, implementing restrictions on real-time video viewing within dugouts.
The Electronic Sign (PitchCom) Debate
MLB introduced PitchCom, an electronic sign system, in 2022. Catchers press buttons on a wrist device, transmitting pitch type and location via audio to the pitcher's earpiece. This fundamentally eliminated sign stealing and improved game pace. PitchCom adoption is being discussed in NPB but has not been formally implemented as of 2024. Cautious opinions cite 'sign gamesmanship is part of baseball,' 'concerns about device malfunction,' and 'cost issues.' Proponents argue for 'fundamental resolution of sign stealing,' 'shorter game times,' and 'improved pitcher-catcher communication.' NPB's PitchCom decision is expected to follow evaluation of MLB's operational track record.
Books on baseball information warfare are also helpful
When Signs Decide Games
Numerous games have been directly decided by sign execution. One famous example is Game 5 of the 2006 Japan Series between Chunichi and Nippon-Ham. Chunichi catcher Motonobu Tanishige's pitch calling was masterful, shutting out the Nippon-Ham lineup. Tanishige later said he 'read opposing batters' intentions and thoroughly executed counter-sequencing.' Conversely, sign miscommunication can cause fatal runs. 'Crossed signs' where pitchers throw unintended pitches cause wild pitches and home runs. Communication is particularly challenging between foreign pitchers and Japanese catchers due to language barriers, requiring careful sign system confirmation through interpreters. Signs represent invisible information warfare, with their precision directly affecting game quality.