front line; forefront; spearhead
Refers to the very front of an advance, battle, or movement; often used in military, competitive, or figurative contexts.
彼は常に最前戦で戦ってきた。
He has always fought on the front line.
その企業は技術革新の最前戦に立っている。
The company is at the forefront of technological innovation.
Compound of 最 (most) + 前 (front) + 戦 (battle/war), literally 'the very front of battle'.