(HBO) – For thousands of years, the Muong ethnic group has demonstrated their Khao Roi (Doi) calendar on 12 bamboo bars that are about 25cm to over 30cm in length. The bars are inscribed with 30 notches representing 30 days in a lunar month. The notches are signs or symbols demonstrating the weather factors or astronomic phenomena believed to affect those days.

As bamboo bars have limited length, ancient Muong people made careful consideration to select symbols to inscribe on them to create the Khao Roi (also called Doi) calendar. 

Basic symbols on Khao Roi calendar:

The Khao Roi (Doi) calendar of Muong people uses simple symbols. 

No.

Symbol

Creation method

Name

Note

Name in Muong language

Name in Vietnamese language

1

 

Carving sawteeth wave

Khoc tinh ngai

Nac tinh ngay (day marking notch)

Short V-shaped lines

2

 

Drilling or carving to create small dots or round holes

Lo kon

Lo nho (small hole)

Holes, dots, zero (0)

3

 

Carving vertical lines

Vach

Vach (line)

Short vertical lines

 

 

 

 

 

 

 These three simple symbols are used to demonstrate Mua (rainy), Ca, Lo and Roi (Doi) days, among others on bamboo bars. 

For example, the V represents the Ca day, the X represents the Khoang Kac days, and a vertical line with small holes atop represents the Doi day. 

Symbol of Khao Roi (Doi) day

Muong people named their bamboo calendar after the Roi (Doi) constellation. The Roi (Doi) day is the one when that constellation passes in front of the moon, once a month.

On bamboo bars, the Doi day is demonstrated with a vertical line with one round hole on top of it and two - three others arranged symmetrically on both sides. 

However, the calendars collected in Lac Son district do not contain the Roi (Doi) day symbol. 

1. Single-factor days

Single-factor days in the Roi calendar are those when only one factor occurs such as the Ca, Hao, Lo and Roi days, according to the Muong folk belief.

 Figure No 1: Symbols demonstrating single factors on the Roi calendar

The Khao Roi calendar of Muong people has eight single-factor days, namely Ngai Lo(Lo day), Ngai Haw(Hao day), Ngai Ka(Ca day), NgaiKhaw Roi (Doi)- Roi (Tua Rua) star day, Ngai Muo Paw(rainy day), Ngai Khwang Kac(Khoang Cac day), Ngai Roi baw(the day when Roi comes), and Ngai Roi tha(the day when Roi goes). 

2. Multi-factor days 

Multi-factor days are those believed to record the occurrence of many factors. In other words, they are the days affected by at least two factors such as Ca and Hao or Hao and Lo appearing on a same day. 

Muong people believe that multi-factor days are bad ones. 

A preliminary survey showed that there are more than 20 multi-factor days in the Khao Roi calendar./.


Related Topics


The Festival of Sim Pagoda in At Ty Spring, 2025

On February 12th (i.e. Lunar January 15), the People's Committee of Hop Tien commune, Kim Boi district organized the Festival of Sim Pagoda Festival in At Ty Spring, 2025. The festival welcomed many people and tourists to visit the pagoda and enjoy the scenery. The palanquin procession to Sim Pagoda.

Hoa Binh ensures safety for spring festivals

As Hoa Binh province is set to host 115 spring festivals, local departments, sectors and localities are joining hands to ensure safety for the events.

Sound of Muong gongs echoes in Hanoi

In many major cultural events in Hanoi, the sound of the Muong people's gongs has become a special tone, contributing to the unique harmony that praises the cultural values accumulated over thousands of years along with the sacred soul of the capital city.

Promoting traditional attire of Muong people

On the first day back to work and school after the Lunar New Year holiday, thousands of female officials, civil servants, and students from grade nine and above in Lac Son district proudly wore the traditional Muong attire. The vibrant brocade patterns created a striking cultural display, reinforcing the community's commitment to preserving and promoting their heritage.

Hoa Binh hosts Muong ethnic minority group's Khai Ha festival

The provincial-level Khai Ha festival 2025 of the Muong ethnic minority group took place at Phong Phu commune’s stadium in Tan Lac district of Hoa Binh province on the morning of February 5 (the 8th day of the first lunar month of the Year of the Snake).

Vibrant celebrations of traditional festivals in Yen Phu, Vu Binh communes

"Xuong Dong” (going to the field) festival opened in Yen Phu commune of Hoa Binh’s Lac Son district on February 5, or the eighth day of the Year of the Snake, drawing thousands of locals and visitors to partake in a variety of activities.