Being an alcoholic with many many years of experience on both sides of wet/dry can tell you there's no way you can win....impossible. Hold it and suffer again. Don't hold it and field some resentments.

Doctors say more than four drinks at one sitting for men, or more than three drinks in one sitting for women, is binge drinking. There's no way you can control the supply since the booze lovers can bring their own or step outside to their own supply.

Does Japan have an equivalent of a dram shop law where you could be held responsible if someone got drunk at your party then hurt themself or someone else on the way home.

Friends once tried collecting all the keys and providing bedding for all the party goers for the night. One of the drunks woke up to relieve himself - in a stupor he relieved himself in a little girls closet. So even key holding can backfire.

Maybe if you had a neutral location you could rent - like some hall somewhere....then the "damage" would remain there.

It sure don't look good. You are very very wise not to ignore the results of past years.