Anecdotally, speaking as someone who knows a number of young people from Singapore, they certainly smoke weed just as much (perhaps even more) than people I know from the UK. Have you considered that perhaps a zero tolerance approach just drives use further underground? I doubt the official figures are accurate, and it's probably not sensible to compare an authoritarian dictatorship with liberal Western democracy.
Japan just has a low crime rate across the board, largely for the reason you mentioned. Again, this probably isn't helpful - inducing a general respect for the law into a society is a difficult proposition, or every nation in the world would be doing just that.
Japan just has a low crime rate across the board, largely for the reason you mentioned. Again, this probably isn't helpful - inducing a general respect for the law into a society is a difficult proposition, or every nation in the world would be doing just that.