Meaning

A single horseman who can take on a thousand foes — used of a fighter whose individual combat power dwarfs that of an ordinary soldier.

一騎で千人を相手にできるほど、ずば抜けて強い戦闘力や能力を持つこと。

The Kyojuro Rengoku moment

200人の乗客を一人で守り抜く戦力 — On the Mugen Train, Rengoku is the sole defender against an Upper Moon demon and the dream-trap creatures, and not one passenger dies on his watch.

Why it fits Kyojuro Rengoku

The Mugen Train arc is the textbook ikki-tōsen scenario: hundreds of helpless passengers, one Hashira, an Upper Moon demon, and a single dawn between them. Rengoku holds the entire line by himself.

Cultural note

Origin in classical / Buddhist / Confucian tradition

From the Chinese Records of the Three Kingdoms tradition; ikki = single cavalryman, tōsen = match for a thousand foot soldiers.

Sources

• デジタル大辞泉 — 一騎当千 (dictionary)
• 精選版 日本国語大辞典 — 一騎当千 (dictionary)

How these sources are vetted →