https://www.hachanna.co.th/en/categories/tojiro-japanese-knife.html
Thai - supposed to be very good.
https://www.cutboyknife.com/
https://www.central.co.th/en/search/kitchen knives
https://www.central.co.th/en/home-lifestyle/cooking-dining/cookware/kitchen-knives
So try Villa Market, Central and other stores who have Henckels, Wusthof, Zwilling etc but I have definitley seen Global somewhere ? Maybe Siam Takashimaya or Emporium?
Maybe ask a Chef in a Japanese restaurant of a hotel where they buy their knives from?
I'm actually visiting Japan in August/Sept so reading up as I want to buy some for a present:
https://www.curated.com/journal/1884000/the-best-japanese-knife-brands