(idiomatic) at the cost of one's life

instead of… in place of…,

substitute, use in place of, replace with, replace something with another

conjunctive form of 誓う (chikau) [godan]

an oath, pledge / (Shinto, Buddhism) vow that the Buddha pledged to save sentient beings

to swear, to pledge, to make an oath, to vow

(Classical Japanese) to be watching continuously, to be on watch repeatedly, to be on look out

(Classical Japanese) to be watching continuously, to be on watch repeatedly, to be on look out / (Classical Japanese) to protect something, to take care of something

(Classical Japanese) to be watching continuously, to be on watch repeatedly, to be on look out / (Classical Japanese) to protect something, to take care of something

(archaic) to stand watch over something, to be on the lookout for something (such as a watchman controlling entry to a place) / (archaic) to protect or defend something, to ensure that something is safe