Overview
The video review system (request system) allows managers to challenge umpire calls and request confirmation via video replay. NPB officially adopted the system in 2018, modeled after MLB's challenge system, with the goal of correcting missed calls and improving judgment accuracy. Reviewable plays include safe/out calls, fair/foul determinations, and home run rulings (whether the ball cleared the fence), while ball/strike calls are excluded. Each team receives two challenge opportunities per game; if a challenge succeeds and the call is overturned, the challenge is not consumed. The system's introduction addressed the long-standing problem of uncorrectable missed calls. Before its adoption, even obvious errors had no remedy, and game-deciding mistakes drew significant criticism. Since implementation, close-play accuracy has improved, and acceptance among players, managers, and fans has increased. However, critics note that review-related stoppages extend game duration. Video confirmation typically takes two to three minutes but can run longer for difficult calls. Balancing technology with human judgment is a challenge that extends well beyond the review system to modern sports as a whole.