Tang Shaoyang arrived in Japan's flying zone in half an hour, but it took him two hours to find the Osaka Castle. If not for the castle, it would take him longer to find where Osaka was. In fact, Osaka Castle was the third castle he found on this trip; it was quite a hassle to find Osaka Castle.
Fortunately, The Taukai Family and The Tachibana Family's territories were next to each other. The Taukai Family occupied Sakai, where Osaka Castle was, and The Tachibana Clan occupied Kyoto. So, the two factions gathered in Osaka Castle. He did not need to go around Japan since both factions came to Osaka Castle.
Tang Shaoyang was sitting in front of the Tachibana Clan and the Taukai Family's leaders, explaining the Sub Region system to them. After that, he directly proposed his idea for the two factions.