The Hunt for Tatsu is the 48th substory in Yakuza Kiwami 2.
At the Iwao Bridge, a suspicious thug stops you asking if you know Tatsu. Tatsu is apparently an arms dealer who specializes in weapons. Kiryu, wanting to know more about this situation, decides to follow the thug down the footpath to see if he can find out more information. On the footpath, the thug is now questioning a homeless man about Tatsu. When you try to intervene, the thug does not take kindly to it and wants to fight you. After fighting him, he tells you that Tatsu is located somewhere nearby in Sotenbori. The homeless man lets you know that on Bishamon Bridge, there is a man named Kinoshita who can introduce you to Tatsu. Kinoshita agrees to let you meet Tetsu if you past his test first. Next, go to Murata and tell him that you defeated Kinoshita and he will call over Tetsu. He arrives in a boat and allows you to purchase unique items and weapons.