also: ちょせん
noun
beginning of hostilities; opening of a conflict
Refers to the initial stage of a war, battle, or military campaign. Often used in historical or news contexts.
緒戦の勝利がその後の戦局を大きく左右した。
The victory at the beginning of hostilities greatly influenced the subsequent course of the war.
noun
first match;
Used in sports or competitions to mean the first match of a series, tournament, or season. Synonymous with 初戦.
See also: 初戦
緒戦で強豪チームと当たることになった。
We ended up facing a strong team in the first match.
初戦 is more common for 'first match' in sports; 緒戦 can also mean 'beginning of hostilities' and is slightly more formal/literary.
Compound of 緒 (beginning, thread) and 戦 (war, battle). The reading しょせん is the standard Sino-Japanese reading; ちょせん is a less common variant.