关门打狗

關門打狗
guānméndǎgǒu
  1. lit. shut the door and beat the dog (idiom)
  2. fig. seal off the enemy's avenue of retreat, then strike hard

CEDICT

to take control of someone in one's sphere of influence and proceed to attack in a highly effective way

Wiktionary

Entry Composition

1 关门 guānmén
  1. to close a door
  2. to lock a door
  3. (of a shop etc) to close (for the night or permanently)
2 打狗 Dǎgǒu Takow, Takao or Takau, old name for Kaohsiung 高雄 Gāoxióng in the southwest of Taiwan