Items not allowed: Knives, scissors (longer than 5.5 cm), poison, illicit drugs, flammable things, flares, fireworks, firecrackers, explosive items, oil, hammers, screwdrivers, chains, ice picks, glass bottles, cans, canned goods, raw eggs, and more.

Plastic (PET) bottle drinks are allowed, but it may be subject to inspection.
Even this sign was not in English. So I guess they weren't expecting foreigners to attend this event.