深刻 is a Chinese word that is the form of intense that describes a person who is deep, serious, and a true thinker.

If you find yourself contemplating the world and coming up with profound ideas, this might be the word for you. In some contexts (especially Korean), it can mean seriousness, gravity, or acuteness.

In Japanese, this can mean “serious problem” or can be a rare given name, Misa. You should not use this if your audience is Japanese.

入木三分 is a four-character Chinese proverb that translates in English to a strong form of “profound” or “written with a forceful hand.”

But there is much more to the story...

The deep meaning behind this proverb comes from a man named Wan Xizhi, who lived in the third century.

He was a great writer and calligrapher whose writing style influenced generations of other writers and calligraphers.

He once wrote words on a piece of wood to be taken to an engraver.
When the engraver began to carve the characters into the wood, he found that Wang Xizhi's writing had penetrated the wood about 3/8 of an inch.

Thus people believed that his words were so powerful and profound that they caused the ink from his brush to penetrate the wood deeply.

The proverb literally means “penetrated wood three fen” (A fen is an ancient Chinese measurement of a little over 1/8 of an inch or almost 4mm).

真剣 is a Japanese word that means intense, serious, or earnest. It describes a person who is deep, serious, and a true thinker or dreamer.

Literally, this means “true sword,” as compared to a sharpened wooden practice sword blank. It's real, true, and serious.