Wang Xizhi (wāng xī zhī 王羲之) is one of the most famous calligraphers during the Eastern Jin Dynasty (dōng jìn 东晋,AD 317-420) of China. When he was very young, he practiced his art every day and never stopped. Later he absorbed the strong points of all the other schools of calligraphy, and developed his own unique style of writing. Because of his achievements, he has been honored as one of China's sages of calligraphy. It is said that a carpenter once found that the ink of the characters Wang Xizhi had written had gone almost one centimeter into the wood because of his forceful stroke." Rù Mù Sān Fēn" is got from this story, which means the calligraphy is penetrating. Now it is often used to describe expressing sharp ideas or profound views.

我国古代大书法家王羲之是东晋时会稽人。他日夜苦练书法,从小已经写得一手好字，后来他博取百家之长,逐步形成自己的风格。因为他在书法上的成就，人们都尊称他为“书圣”。有一次他把字写着木板上，让雕刻师傅照着样子把字刻下来，雕刻师傅发现王羲之的字迹竟然浸入木板有三分深。成语入木三分形容书法用笔功力非常深厚。现在经常用来比喻见解议论非常深刻有力。

入木三分 (rù mù sān fēn)
【翻译】 To enter three-tenths of an inch into the timber.
【释义】 形容书法笔力苍劲有力。比喻分析问题见解很深刻。
【例句】 这部小说对人物的刻画入木三分，情节也很感人，一出版就被抢购一空。
【近义词】 力透纸背 铁画银钩 可见一斑 鞭辟入里
【反义词】 略见一斑 不著边际