He did what the monk told him, and won the battle, he became a famous Samurai afterwards.
Don’t think, and worry too much about something that has already happened that you can’t change. Don’t regret the past. And Don’t worry about things that haven’t even happened yet. Don’t wast your energy anticipating. Most of the things you worry about will never happen.
If you just focus on what you are doing in the moment, you will achieve more than you ever would have imagined.