Don't let the low trophy completion rate fool you -- this is one of the simplest trophies to get in the game! It eludes most players because they simply never go into the pachislot parlors.
You can collect this trophy in the second half of Part 3, or the Finale. "Aladdin A" and "Beast King" are two of the three types of slot machines found at Sunrise in Sotenbori, and Volcano in Kamurocho. Go up and down the aisles until you find them.... then play each of them three times. You don't have to accomplish anything in these games -- entering and exiting the slot machine minigame is sufficient.