early stages of a game; opening phase
Used in sports, board games, and competitive contexts to refer to the initial part of a match or contest.
They took the lead in the early stages of the game.
将棋の序盤戦は駒組みが重要だ。
In shogi, piece development is crucial in the opening phase.
Refers to the final stages or endgame of a match.
Compound of 序盤 (early stage) + 戦 (match, battle). The exact historical derivation is uncertain, but the word is transparently formed from its components.