Release date 21 Oct, 2026

In a Vietnamese family, a death anniversary or the Lunar New Year is never one person s job. Someone buys the offerings, someone cooks, someone drives the grandparents, and someone has to remember which prayer to read. Until now, that planning happened in a group chat, while the reminder lived in our app.

Version 1.0.9 brings the whole conversation into the reminder itself.

Grandma s death anniversary falls on the 15th of the 9th lunar month, a different solar date every year. One aunt lives in Saigon, a cousin is in Melbourne, and the person who usually remembers is busy that week.

Nhat Nguyet was built so that nobody in the family misses it.

One reminder, the whole family

Add the date once, in lunar terms. Everyone in the family group gets it at the same time, wherever they are:

What do I need to prepare for a first death anniversary?

0.0s. Typed into search. The app first works out what kind of question it is: a how-to, not a date and not a calculation. It answers with a passage quoted word for word from our article on the first death anniversary. The footnote points to Phan K B nh s 1915 book on Vietnamese customs.

Tap Set a reminder . Death anniversaries follow the lunar calendar, so the engine converts the date to this year s and next year s solar dates. No guessing.

Two weeks before. The reminder unfolds into a checklist: incense, sticky rice, the five-fruit tray. The tray follows your home region. The North and the South arrange it differently, and the app says so instead of quietly picking one.

Last year my aunt called me at 9pm. Tomorrow is Grandpa s death anniversary. Did anyone order the sticky rice?

Nobody had. Five siblings, three cities, one family chat with 400 unread messages, and the one fact that mattered was buried somewhere in March.

That call is the reason Nhat Nguyet is built around families instead of individuals.

Now the anniversary lives in a family group. My aunt added it once, on the lunar date, and it reaches all of us every year. Two weeks before, a plan appears: sticky rice, fruit, flowers, who drives Grandma. Each task has a name next to it. When my cousin ticks fruit , the rest of us see it. When someone asks three trays or five? , the answer sits under that exact date, not in a chat that scrolls away.

What readings do you actually offer?
Three disciplines: Four Pillars, Purple Star astrology and numerology. Each one comes in different shapes depending on the question you bring:

• a lifetime reading;

• the year ahead, month by month;

• ten years at a glance;

• focused readings on career, money or love;

• two-person readings: a couple, a parent and child, business partners;

• a reading for a child, written for the parents.

Why should anyone trust it?
You shouldn t trust it blindly, and we say so. What we can promise is that you can check it. Every pillar, star position and number is computed by our own engine, the same one behind our lunar calendar, which we cross-check against NASA and IMCCE astronomical data. The language model never invents a number. It only writes prose around facts the engine has already computed. When a reading quotes a classical book, it quotes it word for word, and the book and author are listed at the end.

Where does the knowledge come from?
Months of collecting and buying books, many in classical Chinese, turned into a searchable library with OCR. Readings draw on that library, never on scraped blog posts. Where schools of thought disagree, the reading tells you rather than quietly choosing one.

Vietnamese families still run their year on the lunar calendar: ancestor anniversaries, Tet (Vietnam New year), the 1st and 15th of each month, which day to move house. The knowledge behind it is real, but it lives in old books, in what your grandmother remembers, and in websites that copy each other and rarely cite anything.

I m building Nhat Nguyet to fix that. Here is the order we built it in, because the order turned out to matter more than any single feature.

1. Knowledge first, before any tool

We started with sources, not features: classical texts, academic papers, official records, and reputable newspapers. Every factual claim in an article (a date, a number, a book title, a quote) carries a footnote to a specific source. If the source doesn t say it, the sentence gets rewritten or removed.

Spirituality and astrology apps have an easy business model and a sustainable one, and they are not the same. The easy one: tell people something is wrong with their year, then sell the fix. It converts well for a month and burns trust for good. Here is what we think the sustainable one needs.

1. Knowledge solid enough to stand behind

You can t build trust on content you don t understand yourself. Every claim needs a source, and every result needs to say which part is calculation, which part is tradition, and which part is one school s rule. If you can t explain where an answer comes from, you shouldn t charge for it.

2. Safety first, logic over superstition

I'm from Vietnam. I've spent 18 years in software, data and AI, and for the past months I've been building Nhat Nguyet. I'd like your view on the idea behind it.

The problem

Vietnamese customs and spiritual beliefs are scattered. They live in older relatives' memory, in classical Han Nom books few people can read, and online in pages copied from site to site with no sources. My generation works far from home and is losing the dates and the reasons behind the rites. That gap gets exploited: families are told to pay for rituals to remove bad luck, buy charms, or fear certain days, with no way to check what the tradition actually says.

Our approach: knowledge first