In Vietnamese society, people gathered together to form villages in rural areas and guilds in urban areas. These villages and guilds have been forming since the dawn of the nation. The organization gradually developed, steadily becoming more stable and closer together. Each village and guild has its own conventions.
The purpose of the conventions is to promote good customs within populations and organizations. All are different, but of course are always in accordance with state law.
There are tens of thousands of such conventions safety kept in the History Museum in Hanoi and other museums throughout the country