While you are feeling happy to be granted a patent, others may raise an opposition to your patent.

An opposition is allowed for six months after the patent publication is issued.

In the 30 months from April 2015, the number of oppositions were 2512.
35% of the patents were maintained as they were, 51% were partially corrected, and 12% were partially or totally revoked.

Two- thirds of patents reights were narrowed or revoked.
It’s quite tough.

https://www.100man-pat.jp/en/