bì qí ruì qì , jī qí duò guī
avoid the enemy when he is fresh and strike him when he is tired and withdraws (idiom)
避
bì
to avoid
其
qí
his
锐
ruì
acute
气
qì
gas; air
,
,
击
jī
to hit
惰
duò
lazy
归
guī
to return