It was announced in Riot Games ONE event and confirmed.
I am Korean, but I agree with this choice very much because Japan valorant is much more popular than Korea valorant
Probably a logistics thing really. Lot easier to get Visa's and the infrastructure is already there from running league of legends lan based leagues there already
WE CAN FINALLY WATCH VALORANT WITHOUT SACRIFICING 100 YEARS OF OUR LIFESPAN W RIOT