Found this place by just walking around randomly, trying to get from one place to another by going in the wrong direction. I like it when it works like that. It was a Monday, and the sign said the place was closed on Mondays and yet nevertheless:
That, I think, is incredibly rare. I have lost count of the times I've tried to go somewhere because the internet, or the flyer says it will be open only to find that it's closed (Maruyama Drill Hamburger Shop, I'm looking at you). So to find somewhere that says it'll be closed only to be open is an early Christmas present.
Suriyothai is in a building that looks fancy from the front, but to get to the restaurant you have to go through to the back where there's a little hidden line of bars and shops which looks far less glamorous. They do mostly Thai curries in the well known "Traffic Light Arrangement" (red curry, yellow curry or green curry) and a bunch of other Thai influenced food. I got the impression that if you went for something spicy at this place, you'd really get something spicy...
We got the green curry and a rice dish that was apparently a drier Thai curry to be eaten with rice. Since the place doesn't look at all fancy, and yet has a 'Top 100 restaurants in Hokkaido' sign outside from a few years back, I wasn't all that surprised to find that the food was excellent. Like I said, I think things might get spicy if you want them too - I don't mind that with some things but I've had bad experiences with Thai food so I didn't push it. Oh and there's a terrifying looking pot of extra spiciness on the table should you feel so inclined.
Looking this place up I found that there was a Japanese youtube channel devoted to Thai restaurants. They basically just walk in and spin around a bit, but here, so you can experience it all the more powerfully, is their video of Suriyothai:
Awesome. Suriyothai is very close to Kita 12 Jo station, and if you like Thai food than absolutely check it out. It's on my map!