BLAM was the first airsoft “field” I ever played at. After having played in parks for a few months I decided to see if there were places in Japan where you could actually play as a group that wasn’t putting others at risk. I didn’t discover airsoft as part of a group or through friends, it was more of an organic discovery that started with the purchase of a P99 GBB…BLAM was my first attempt at joining and being a part of the airsoft “community.”
Here are the relevant details…
Type: Indoor warehouse CQB
Location: Taxi, bus, or long walk from Shintokorozawa Station on the Seibu-Shinjuku Line, Saitama
Schedule:
Mon – Fri: 14:00 – 00:00
Sat & Sun: 12:00 – 22:00
CLOSED Thursday
Regulations:
.98J with .2g BB
BLAM recently updated their power regulation as new guns are starting to be more powerful out of the box. They used to have a .8J limit (90m/s) but you can now use guns all the way up to .98J! However, any gun shooting over .8J has to use .16 or .12 gram BBs.
BLAM has public games on the second and third Saturday as we as the fourth Sunday of every month. This is an open house where all players show up and create two mixed teams that play against each other from 10:00 until 17:00. From 17:00 until closing they allow free play.
Their regular game system is to have people show up as a team and play as your own group or, if willing, against another team. Games are based on a 15 minute rotation, so you get more games if you play against another team, but if there are too many teams you can get stuck in a 2 or 3 game rotation and only play for 15 minutes per hour 
Solo players are welcome and will get assigned to a team.
Rentals are available for 500 yen a day. This does not include BBs
Cost is 500 yen per 15 minute game or 3500 for the entire day (500 yen off if you reserve 3 days in advance with their online booking system).
They also offer a weekday evening discount rate…
1500 yen from 18:00 – 00:00
1000 yen from 21:00 – 00:00.
They also have some regular scheduled events on weekends like APS cup practice, Action shooting, target range shooting, etc.