Uchikomi

Uchikomi refers to a deep invasion into the opponent’s territory. 

Unlike shallow reductions, an uchikomi often seeks to live locally or provoke a large-scale fight.

The word uchikomi (打ち込み) literally means “striking into” or “driving in,” a fitting metaphor for this aggressive tactical maneuver. While the term is rarely used in English outside of technical Go literature, it remains common in Japanese.

Historically, uchikomi also refers to a system of handicap adjustment. Before the advent of komi (compensation points for White), players of different strengths would follow a structured handicap system. When a player lost four consecutive games, they would be “beaten down” (uchikomi) to the next handicap level—moving from tagaisen (even games) to sen-ai-sen (Black twice in three games), or from sen-ai-sen to josen (always Black), and so on.