叩首 is read as こうしゅ (koushu) and means kowtow.
こうしゅ
koushu
はたき
(feather) duster
たたき
finely chopped fish or meat (sometimes seared first)
たたく
to beat down the price
くび
head
ちくび
nipple
げんしゅ
sovereign
てくび
wrist
あしくび
ankle
じしゅ
surrender (to the authorities)
とうしゅ
party leader
ぶしゅ
radical (of a kanji character)
いっしゅ
one tanka