Welcome to drinking in Japan! This may be what happens to you when you drink in a country that has no blue laws, where liquor licenses do not exist, there are no open container laws, and never had Prohibition or a Gin Craze. Which is to say that when it comes to controlling your intake, you're truly on your own. Bartenders will not cut you off for being too drunk, so long as you're capable of ordering. The phrase "please drink responsibly" is especially important in Tokyo because you're not driving anywhere, it's perfectly legal to be drunk in public, and you'll have unfettered access to alcohol anywhere anytime.
So in Tokyo: please drink responsibly... because nobody else will stop you!