Vietnamese customs were scattered across a thousand web pages, so we built one sourced map of them

Ask ten Vietnamese families how they hold a death anniversary and you get ten answers. In the Red River Delta many make the first offering the afternoon before; in the Mekong Delta plenty do it on the day itself. Tày families invite a Then master, Khmer families go to the pagoda. All of these are real. Almost none of it is written down in one place. What exists online is mostly the same few pages copied and recopied, each copy a little different, none saying where it came from.

So instead of writing more articles, we built a structure first. Every rite in Nhat Nguyet is recorded the same way: its cycle and lunar date, where it’s performed, who is honoured, which ethnic group and cultural region it belongs to, the order of the ceremony, the offerings, the taboos. Each of those fields carries its own source.

The sources come in layers. At the bottom are scholarly books, mostly public domain now: Phan Ke Binh’s Vietnamese Customs from 1915, Nguyen Lien Phong’s 1909 verse record of southern customs, Dao Duy Anh’s 1938 cultural history, Toan Anh’s work from the 1960s. On top of those, recent research by Ngo Duc Thinh, Tran Ngoc Them and Dinh Khac Thuan. Then heritage files: UNESCO nominations for the Giong Festival, Hung Kings worship and Then practice, plus ritual records from the Hoi An heritage centre. Press articles only count if they come from a list of 124 vetted sources.

The prayer texts were the hardest part. We collected them from 717 pages and kept every one word for word, no edits, no translation. Many turned out to be near-copies of each other with a few words changed, so those were merged and only genuine variants kept. Every lunar date was recalculated by our own calendar engine, which is checked against NASA new-moon data. Anything without a source was dropped. Rites that belong only to members of a community are listed but their steps aren’t published.

For geography we used Professor Ngo Duc Thinh’s seven cultural regions and the official list of 54 ethnic groups. Today that adds up to 155 rites, 438 prayer texts on their own pages, 232 kinds of offerings, 176 questions and answers, and pages for 7 regions and 16 ethnic groups. Six datasets from it are open under CC BY 4.0.

It’s still uneven, and we’d rather say so. 354 of the 464 prayer texts come from sources that never say which region they belong to; only 10 are tied to the North. Only 29 of the 155 rites have had a second review. 38 of the 54 ethnic groups don’t have a page yet, mostly because very little has been published about them.

That’s the part we’d most like help with. If your family does something the database doesn’t describe, or describes wrongly, we want to hear it, and every correction gets logged on a public page.

https://nhatnguyet.org/en/phong-tuc-viet