一张一弛 (一張一弛) yī zhāng yī shǐ

yī zhāng yī shǐ set phrase alternately tightening and relaxing; tightening and relaxing as appropriate
Domain: Idiom 成语 , Subdomain: , Concept:
Notes: (Guoyu '一張一弛'; Mathews 1931 '一張一弛', p. 20)