Originally Posted by
greendx
If you're in Minato-ku area this place
http://www.sushinomidori.co.jp/shop.php?name=akasaka which is apparently another chain, is very good. I stumbled on to this location walking around in the area near my hotel and have gone back to it again on another visit. Don't recall seeing any other tourists on either visit. It's a bit more expensive than Zanmai and is good to go for set menus that have ~12 sushi pieces rather than ala cart.
You must have gone during a lull. The Midori chain is a favorite of ferners as it's in every guidebook these days. Or they could have been other Asians. They love that stuff.