Osaka is a really cool city to visit; very different energy/atmosphere from other Japanese cities. From Tokyo it’s only about 2 and a half hours by Bullet Train, so definitely make the trip if you have time!
For the arcades, you will want to go to Namba Station (you can use the subway or the train, but they go to different stations). Use http://www.hyperdia.com to find out the best way to get there. The big arcades are conveniently located on the same street, in an area surrounded by shopping, restaurants, hotels, and more. It’s great!
From the Subway Station, it’s about a 10-15 walk. If you get off at the Train Station, then the arcades are right outside! Anyway, on to the arcades…
ATHENA: This is the place to go to for non-Capcom games- BB/P4U/AH3/whatever. It’s a little small, but the players are very welcoming and friendly. This is a HIGH LEVEL arcade, so if you’re a lower level player, better to practice at one of the other spots.
AVION: Big Fighting Game floor; good balance of games + skill levels. It seems to be the main Capcom arcade in the area- many high level SF4 players when I visited. This arcade is the main arcade for tournaments/events.
TAITO STATION: Every time I visited here, it seemed to be very low-level/casual spot for FG’s. Good for practice?
NAMCO- Only Tekken + Gundam machines, but very busy and popular for those games. It’s worth a visit to see the Tekken Museum and the Ring!
That’s it, those are the Big Four! There are more Osaka arcades, but they’re at different stations so it’s best just to head to Namba. If you need a place to crash at, I circled the location of a great capsule hotel on the map. 2500 yen/night, very convenient location and nice baths! Give it a try, you can make reservations here (but even without a reservation you can get a spot)- http://daitoyo.co.jp/amza/
As usual, if you have any questions or you want me to introduce some Osaka players to you, just hit me up on Twitter @jiyunajp !