helmet (of a warrior), headpiece

rhinoceros beetle (esp. the Japanese rhinoceros beetle, Trypoxylus dichotomus)

horseshoe crab

Tusita (heaven, pure land)

large-headed midnight fish (Poromitra crassiceps), armored fish, armoured fish

tadpole shrimp (Triopsidae spp.), shield shrimp

broiled fish head (esp. sea bream)

tokin, small black headgear worn by yamabushi

Kabutochō (neighbourhood of Nihonbashi, Tokyo, where the Tokyo Stock Exchange is located)...

steel helmet

inside of a helmet, hidden circumstances

aconite (esp. species Aconitum japonicum), wolfsbane, monkshood...

spiked helmet

broiled fish head (esp. sea bream)

to accept one's inferiority, to take one's hat off to someone, to give up...

helmet-shaped hood

Tusita heaven (one of the six heavens of the desire realm), Tushita

tadpole shrimp (Triopsidae spp.), shield shrimp

to accept one's inferiority, to take one's hat off to someone, to give up...

frot (sex act)

zunari helmet (made from 3-5 pieces of metal)

Pandanus boninensis (species of screw pine)

Hercules beetle (Dynastes hercules)

do not let your guard down after a victory, tighten the strings of your helmet after winning