Today’s kotowaza, in English terms, is more of a set phrase than a “saying,” but it’s a kotowaza in Japanese none the less.
(Haisui no jin; “An army with its back to the water”)
Having your back to the wall. Being backed into a corner. A tight spot without room to maneuver in. A situation where, if you mess up or fail, there are no second chances: you can’t regroup and try again.
The nouns 背 (“back,” in the compound pronounced with the Chinese-based reading hai) and 水 (“water,” similarly pronounced sui) make what is effectively a compound noun. The associative particle の (no) connects it with the noun 陣 (jin), a military camp or formation. So 背水の陣 depicts an army drawn up for battle with its back to a river, lake, sea, or other body of water.
Like so many others, this phrase comes from Chinese antiquity – specifically the Battle of Jingxing, in which the Han general Han Xin purposefully arrayed his forces with their backs to a river so that they would fight more fiercely.
(“Kotoshi goukaku shinai to, chokin ga soko wo tsuite shimau nda. Konkai no nyuugaku shiken wa haisui no jin no tsumori de ganbaru!”)
[“If I don’t pass this year, my savings are going to run out. I’m going to work on the next entrance exam like it’s victory or death.”]