My guess is that they want to encourage the "National" service subscriptions as each gym had different on/off schedules.
I had experience with both the Kyoto (Kawaramachi-dori) and Tokyo (Shibuya) gyms myself; pretty decent if too stuffy during winter season.
Yeah, but every Friday? That's the most important workout day -- gotta bulk up the gun show for the weekend. That also means 4 (or 5) a month, after paying 13,000 yen for "a month" subscription. The public gym in Sendagaya is back open (Olympic sized pool: score). However, they fucking close for a week or so for maintenance every now and again. Total ass fuckers. But, they dropped their full time price. It's like 5800 yen a month for me which is a bargain.
Though for similar reasons as yours, I switched to Tipness as they had more flexible service hours; it didn't last due to the 2011 Tohoku incident though.
Tipness manages this one, even though it's owned by the Metropolitan government. I hate Tipness for the most part. I won't go into the reasons now, but Japanese gyms, while clean, miss the boat in a lot of ways.
