赤膊上阵

lit. to go into battle bare-breasted (idiom) / fig. to go all out / to come out in the open

red / scarlet / bare / naked

bare to the waist

shoulder / upper arm

used in 上聲|上声[shang3 sheng1]

(bound form) up; upper; above; previous / first (of multiple parts) / to climb; to get onto; to go up / to attend (class or university) / (directional complement) up / (noun suffix) on; above

to go into battle

disposition of troops / wave / spate / burst / spell / short period of time / classifier for events or states of short duration