Past Experience is the Teacher for the Future in Chinese / Japanese...

The most literal translation to English of this ancient 前事不忘后事之师 Chinese proverb is:
“Past events not forgotten serve as teachers for later events.”

However, it's been translated several ways:
Don't forget past events, they can guide you in the future.
Benefit from past experience.
Past experience, if not forgotten, is a guide for the future.
Past calamity is my teacher.
A good memory for the past is a teacher for the future.
The remembrance of the past is the teacher of the future.
If one remembers the lessons of the past; They will serve as a guide to avoid mistakes in the future.

The origin:
This proverb comes from the 5th century B.C., just before the Warring States Period in the territory now known as China.
The head of the State of Jin, Zhi Bo, seized power in a coup. He did this with help from the armies of the State of Han and Wei. Instead of being grateful for the help from Han and Wei, he treacherously took the land of Han and Wei. Never satisfied, Zhi Bo employed the armies of Han and Wei to attack and seize the State of Zhao.

The king of Zhao took advice from his minister Zhang Mengtan and secretly contacted the Han and Wei armies to reverse their plans and attack the army of Zhi Bo instead. The plan was successful, and the State of Zhao was not only saved but was set to become a powerful kingdom in the region.

Zhang Mengtan immediately submitted his resignation to a confused king of Zhao. When asked why, Zhang Mengtan said, “I've done my duty to save my kingdom, but looking back at past experience, I know sovereign kings are never satisfied with the power or land at hand. They will join others and fight for more power and more land. I must learn from past experiences, as those experiences are the teachers of future events.”
The king could not dispute the logic in that statement and accepted Zhang Mengtan's resignation.

For generations, the State of Zhao continued to fight for power and land until finally defeated and decimated by the State of Qin (which led to the birth of the Qin Dynasty in 221 B.C.).