突破口 とっぱこう Meanings Noun breakthrough (research, etc.); breach; opening Kanji 突 thrust. Read as トツ. 破 break 口 mouth. Read as コウ. Common phrases 突破口になる Words containing 突破口 突破口を開く (とっぱこうをひらく) to make a breakthrough Jinuma: Japanese Dictionary · Word lists