TL;DR: The first death anniversary, or tiểu tường, is held when one year has passed since the death, counted by the lunar calendar from the date of death. Zhu Xi's Gia lễ does not count leap months and uses the first anniversary of the death, so the first anniversary keeps the same lunar date as the date of death in the following year. Some count a full 12 lunar months, leap month included; when a leap month falls in between, that method gives a date one month earlier. If the person died in a leap month, the anniversary the next year is held in the regular month of the same number.
What is the first death anniversary (tiểu tường) and why must the date be calculated?
The first death anniversary is the memorial ceremony marking one full year since the date of death, also called lễ tiểu tường. According to Phan Kế Bính's book Việt Nam phong tục, when one year has passed the family holds the giỗ đầu, called lễ tiểu tường; at that point the heavy mourning items such as hemp garments, the mourning staff and the mourning cap are set aside, but mourning dress is still worn until the full three years have ended[1].
The first anniversary is counted by the lunar calendar, so a year with a leap month raises a question: keep the same lunar day and month as the date of death, or count a full 12 lunar months including the leap month. When a leap month falls between the date of death and the first anniversary, the two methods give dates one month apart.
Why does a leap year make calculating the anniversary difficult?
The Vietnamese lunar calendar is lunisolar: months follow the Moon, and to keep in step with the seasons, roughly every two to three years a year has 13 months, with one leap month added. When the leap month falls between the date of death and the first anniversary, the span from the date of death to the same lunar date in the next year is 13 lunar months, not 12.
For example, a person died on the 10th day of the 8th lunar month of Giáp Thìn, that is 12 September 2024. The year Ất Tỵ has a leap 6th month. Keeping the same lunar date, the first anniversary is the 10th day of the 8th month of Ất Tỵ, that is 1 October 2025; counting a full 12 lunar months, with the leap 6th month counted as a month, it is the 10th day of the 7th month of Ất Tỵ, that is 1 September 2025.
What do the family ritual books and folk custom say?
Zhu Xi's Gia lễ (Family Rituals), in its section on mourning, notes under tiểu tường: "自喪至此不計閏凡十三月", meaning that from the death to this point, without counting leap months, there are thirteen months in all (the month of death counts as the first, so this is one full year). It adds that in ancient times the day of the sacrifice was chosen by divination, while "今止用初忌以從簡易": now only the first anniversary of the death is used, for simplicity. Under đại tường it notes "自喪至此不計閏凡二十五月亦止用第二忌日祭", and under đàm "自喪至此不計閏凡二十七月". So in Gia lễ leap months are not counted, and the first anniversary is the same lunar date as the date of death in the following year.
The count of a full 12 lunar months appears in some guidance: the advice column of Giác Ngộ newspaper (2023) says tiểu tường is held after 12 months and đại tường after 24 months from the date of death, and gives the example of a person who died on the 20th day of the 8th lunar month of 2022: because 2023 had a leap 2nd month, the first anniversary moved to the 20th day of the 7th month, and from the third year on the anniversary keeps the 20th day of the 8th month.
In folk custom, many households keep the first anniversary on the same lunar date as the date of death in the following year, regardless of whether that year has a leap month.
So when the year has a leap month, how should the first anniversary be calculated?
There are two methods; the family should choose one and write it down so that later years are not confused.
The first method keeps the same lunar day and month as the date of death in the following year and does not count the leap month. This is the method of Gia lễ; Phan Kế Bính says only that the first anniversary comes after one year[1] and does not discuss leap months. Nhật Nguyệt's Life-cycle rite dates tool uses this method for its main result.
The second method counts a full 12 lunar months from the month of death, with the leap month counted as a month. When a leap month falls between the two points, this method gives a date one month earlier than the first. Nhật Nguyệt's tool shows the date by this method alongside whenever the two methods differ.
Comparison table of ways to calculate the first anniversary in various cases
| Case | Same lunar date (Gia lễ) | Full 12 lunar months, leap month included |
|---|---|---|
| No leap month between the date of death and the first anniversary | The same lunar date as the date of death, next year | Same as the left column |
| A leap month in between, e.g. died 10/8 Giáp Thìn (12 September 2024) | 10/8 Ất Tỵ (1 October 2025) | 10/7 Ất Tỵ (1 September 2025) |
| Died in a leap month, e.g. 10th day of the leap 6th month of Ất Tỵ | 10th day of the regular 6th month, next year | Also the 10th day of the 6th month, next year |
Points to keep in mind when holding the first anniversary in a leap year
First, record the lunar date of death together with the can chi year, and note whether that month was a leap month; without this detail the date is hard to look up correctly the following year.
Second, the second anniversary (đại tường, two years) raises the same question: Gia lễ does not count leap months and uses the second anniversary of the death, while the month count takes a full 24 lunar months. From the third year on, the anniversary usually keeps the lunar date of death.
Third, according to Phan Kế Bính, between tiểu tường and đại tường there are two burnings of votive paper; by custom they are often done at Trung nguyên in the seventh month, and many families burn them on the first and the second anniversaries[1].
Fourth, the 49th day (chung thất) and the 100th day (tốt khốc) are counted in days from the date of death, so a leap month does not move them. Only the points counted in months or years, such as the first and second anniversaries and đàm tế, are affected.
Should the leap month be added when holding the first anniversary?
According to Gia lễ, no: the book says plainly "不計閏", leap months are not counted, and the sacrifice is held on the first anniversary of the death. The full 12-month count does treat the leap month as a month, so its first anniversary comes one month earlier than the same lunar date in the following year. Both methods have followers; what matters is that the whole family keeps to one.
