In 632 BC, Duke Wen of the Kingdom of Jin was about to lead an army against the forces of the Kingdom of Chu.
The Duke asked one of his advisers, Jiu Fan, how they could win the impending battle, as they were drastically outnumbered.
Jiu Fan said, “All is fair in war,” and suggested a plan of dishonorable tactics (cheating).
The Duke was unsure of this advice, so he asked another adviser, Yong Ji, who replied, “If you catch fish by draining the pond, you can certainly get all the fish. But there will be no fish the following year. You can cheat this one time in battle, but such tactics can only be used once, as the enemy will be wise in future encounters.”

The Duke heard the words of his wiser adviser but cheated to gain victory in the battle. However, he rewarded Yong Ji more than Jiu Fan at the victory celebration, stating that while Jiu Fan's advice gained one victory, the wise words of Yong Ji would last forever.

This Chinese idiom/proverb is still used, over 2600 years later to remind people not to burn bridges, cheat, or dishonor themselves in exchange for a short-term gain while sacrificing the future.

竭澤而漁 is very similar to the meaning of the English phrase, “Kill the goose that lays the golden eggs.”

水の心 is the Japanese Buddhist and martial arts phrase, “Mizu no Kokoro,” which means “mind like water” or “heart of water.”

The phrase is a metaphor describing the pond that clearly reflects its surroundings when calm but whose images are obscured once a pebble is dropped into its waters.

In Japanese, 無心 means innocent or without knowledge of good and evil. It literally means “without mind.”

無心 is one of the five spirits of the warrior (budo) and is often used as a Japanese martial arts tenet. Under that context, places such as the Budo Dojo define it this way: “No mind, a mind without ego. A mind like a mirror which reflects and dos not judge.” The original term was “mushin no shin,” meaning “mind of no mind.” It is a state of mind without fear, anger, or anxiety. Mushin is often described by the phrase “Mizu no Kokoro,” which means “mind like water.” The phrase is a metaphor describing the pond that clearly reflects its surroundings when calm but whose images are obscured once a pebble is dropped into its waters.

This has a good meaning in conjunction with Chan / Zen Buddhism in Japan. However, out of that context, it means mindlessness or absent-mindedness. To non-Buddhists in China, this is associated with doing something without thinking.
In Korean, this usually means indifference.

Use caution and know your audience before ordering this selection.

More info: Wikipedia: Mushin

During the Tang Dynasty, a man named Jia Dao (born in the year 779), a well-studied scholar and poet, went to the capital to take the imperial examination.

One day as he rides a donkey through the city streets, a poem begins to form in his mind. A portion of the poem comes into his head like this:

“The bird sits on the tree branch near a pond,
A monk approaches and knocks at the gate...”

At the same time, he wondered if the word “push” would be better than “knock” in his poem.

As he rides down the street, he imagines the monk pushing or knocking. Soon he finds himself making motions of pushing and shaking a fist in a knocking motion as he debates which word to use. He is quite a sight as he makes his way down the street on his donkey with hands and fists flying about as the internal debate continues.

As he amuses people along the street, he becomes completely lost in his thoughts and does not see the mayor's procession coming in the opposite direction. Jia Bao is blocking the way for the procession to continue down the road, and the mayor's guards immediately decide to remove Jia Bao by force. Jia Bao, not realizing that he was in the way, apologizes, explains his poetic dilemma and awaits his punishment for blocking the mayor's way.

The mayor, Han Yu, a scholar and author of prose himself, finds himself intrigued by Jia Dao's poem and problem. Han Yu gets off his horse and addresses Jia Bao, stating, “I think knock is better.” The relieved Jia Bao raises his head and is invited by the mayor to join the procession, and are seen riding off together down the street, exchanging their ideas and love of poetry.

In modern Chinese, this 反復推敲 idiom is used when someone is trying to decide which word to use in their writing or when struggling to decide between two things when neither seems to have a downside.