No great work gets done in under twenty or thirty years.

The source

"No great work gets done in under twenty or thirty years." Yamamoto Tsunetomo said it in Hagakure, Book 1. Translated from the original Japanese by Spartan Surfers.

"二十年三十年して仕果す事にならでは、大功は無きものなり。"

Original Japanese, Hagakure, Book 1. Japanese: Hagakure, vol. 1 (1937 printing), NDL digital text.

Who said it

Yamamoto Tsunetomo (1659–1719). Samurai turned monk whose spoken reflections were written down as Hagakure, Hidden by Leaves.

Questions

Who said "No great work gets done in under twenty or thirty years."?

Yamamoto Tsunetomo (1659–1719). Source: Hagakure, Book 1.

What is the original Japanese?

二十年三十年して仕果す事にならでは、大功は無きものなり。. Translated from the original Japanese by Spartan Surfers.