Former Konishi Liquors is sort of the first dungeon in Persona 4.
Enter the dungeon and let the story play out between Yosuke and Saki’s voice. After the dialogue, a Shadow will appear.
Boss Battle: Shadow Yosuke
Wind of Oblivion: Light Wind damage
Attack: Normal Physical damage
Guard: Greatly reduces damage
Power Charge: The next attack will be twice as powerful
The first attack should be Wind of Oblivion. This attack can knock you down, leaving you open for more attacks which will do bonus damage while downed.
Once you get back up, use Zio to knock Shadow Yosuke down and get another turn. With it down, use the Cleave ability to do more damage.
From time to time Shadow Yosuke will guard itself. Guarding will greatly reduce the damage you cause. When Shadow Yosuke is done guarding, it should use the Wind of Oblivion attack again. If you’re guarding when Wind of Oblivion hits, it won’t knock you down, so make sure you guard right after Yosuke uses guard!
If playing on harder difficulties, don’t forget to use items like medicine to heal your HP. There’s also the Rakukaja skill that raises your Defense for three turns.