Tensai Bakabon

Whenever you are walking on the street, there is a character that is seen running wildly. Touch him to engage a conversation and choose "strike" (middle option) to beat him up and get 10,000 yen. You can strike him up to five times for a total of 50,000 yen every time you encounter him.

Once you obtain the secret of accessing the underground tunnels by jumping on the manholes three times (you must buy a drink from the bar which you get kicked out then go back in and by a beer to do so). Go inside the first tunnel and the rocks in this area will be arranged to spell out Bakabon in Japanese Katakana.