During Saejima’s story in Yakuza 5, you’re going to wind up at Bar Ambitious. After a bit of pool playing and cajoling, you’ll be directed to a homeless man named Old Man Kiyotaka. You can find him on Kitokouji Street, and once you do, he’ll ask you how many homeless people there are in the city. Answer him correctly, and he’ll give you the info you need to continue in the story.
There’s a couple ways to go about this. If you head down the road, you’ll see a male NPC in a suit near one of the stores. Speak to him, and he’ll mention the answer. Alternatively, you can get the homeless man a beer, and he’ll give you the information you need. If you feel like doing neither of those, you can enter the answer (71) and move on with your life.
Old Man Kiyotaka will give you a photo of a phone booth near Snow Festival Park. There, you’ll answer the phone and receive information on a lottery stand. From there, you’ll head to the stand and answer a series of questions (the answers are Middle, then Bottom, then Top). Then, you’ll get a casino entry ticket and be on your way back to Bar Ambitious.