eli5 How can they sell joints in Osaka?


Im going to Japan in the summer. And a friend of mine who im traveling with sent me a video of a thrifting district that also has a «adult grass» store in it called Cannabis Culture Japan.
I know japan is pretty strict with its drug politiets but somehow this is is legal and a loophole. Tried reading about it, but did not understand anything. Could someone explain?

In: 5

They sell kiken, which are designer drugs. THC is illegal in Japan, but a drug that is synthesized in a lab that is almost THC, but is not actually THC is totally legal.