Refers to a forced march of prisoners or captives under harsh conditions, often resulting in death. Also used metaphorically for an exhausting, relentless task or project.
The prisoners of war were forced on a death march.
This project is truly a death march.
Compound of 死 (し, 'death') + の (possessive particle) + 行進 (こうしん, 'march'). The term is a direct translation of the English 'death march' and is used in both historical and figurative contexts.