tóu tóu shì dào

头头是道 (頭頭是道)

well-argued; coherent and convincing; clear and logical; systemic and orderly

Example:

他说得头头是道。
Tā shuō de tóutóushìdào.
What he said was clear and logical.

战争的学问, 有些人可以在书本上讲得头头是道, 但打起仗来却不一定能取胜。
Zhànzhēng de xuéwen, yǒuxiē rén kěyǐ zài shūběn shàng jiǎng de tóutóushìdào, dàn dǎ qǐ zhàng lái què bù yīdìng néng qǔshèng.
Some people may appear impressive when discoursing on military science in books, but when it comes to actual fighting, they may not be able to win a battle