I learnt it from a chef in Japan in 2009, and I assume he had been doing it for many years at that time.
Generally, that's something done at a sushi train restaurant where the dishes won't have wasabi in them already. I'm guessing these notes are for a sushi restaurant where the chef prepares the sushi specifically for each customer, so if you wanted wasabi they'd put it in the sushi itself.
It's a very chill game, but you can make it as stressful as you want by trying to do everything.
There's no time limit, you can play for as many years as you want, so don't stress and try and get everything done as fast as possible (unless that's fun for you).
The eruption was in 2022 though, so what caused the hole to increase so dramatically from 2019 to 2020?