Where does the expression tchin tchin come from?

No, it's not! It is not the noise caused by the impact between two glasses that creates the expression "tchin-tchin".

In 1900, during the Chinese campaign, French soldiers were in the Canton area. To invite people to drink, they said 'je vous en prie', or in the original version 'tchin tchin'. Once back home, these soldiers kept this way of toasting and started a trend. In China, to say "tchin tchin" is Gānbēi, while in Japan it is Kanpai. But why do we toast?

To understand the origin, we have to go back to the Middle Ages, when poisoning was common. The two liquids were mixed together by violent toasts. This is the same reason why people looked into each other's eyes when they took the first sip: to prevent a poison from being poured into the glass, and not the reason we know today.