Celebrating Birthday Based on Weton Calculation by the People of Blitar, East Java 
Jurnal Indonesia Sosial Teknologi, Vol. 5, No. 7, July 2024                                                   3137 
Weton in Javanese Culture 
Weton can be interpreted as the day of birth. The word weton comes from the 
Javanese language "Wetu" which means out or born., then gets a suffix which makes it a 
form of noun. The so-called weapon is a combination of the day and the market when the 
baby is born into the world. So the word weapon is a combination, gathering, unification, 
or  addition  of  a  person's  best-selling  days,  namely  Sunday,  Monday,  Tuesday, 
Wednesday,  Thursday,  Friday,  and  Saturday  with  market  days,  namely  kliwon,  legi, 
paying, pon, and wage. Weton is sometimes called Petung Weton (Rizaluddin, Alifah, 
Khakim, & Geertz, 2021). 
Weton  or  birthday  in  Javanese  culture  is  a  very  important  thing.  In  Javanese 
calculations, the traits and journey of a person's life can be read from the Weston or the 
day of birth. In Javanese philosophy, the knowledge or record about this is also called 
"Ilmu Titan" or the cool language "Observation Science" or the knowledge obtained and 
compiled  by  the  ancestors  of  the  Javanese  people  in  the  past  from  the  results  of 
observations and then recorded, and become a kind of life guide for the Javanese people 
today (Ashari, 2020). 
The calculation of weapons which is based on Javanese heritage is also a form of 
inherited tradition. The tradition of calculating weapons is also carried out in an event to 
commemorate  the  day  of  birth.  The  tradition  of  calculating  Weston  is  still  widely 
practised by the Javanese people, although not all people follow this culture and believe 
in the celebration of birthdays and the selection of good days (Jihan’Aatika, Maulani, & 
Rifqi, 2023). 
The Javanese Islamic calendar is a combination of the Saka calendar and the Hijri 
calendar. The Saka calendar is based on the earth's circulation around the sun, which 
began in 78 AD, during the coronation of Aji Saka as the king of India, known as the 
Saka legacy. The Javanese or Saka calendar began to be used in 1633 AD or 1544. At 
that time, Sultan Agung Only Krakusuma was the king of Mataram and was known as a 
person who was obedient to Islam, he was also an expert in the field of Falak, the Javanese 
calendar in a revolutionary way. This change in the Javanese calendar starts from Friday 
Legi, 1 Suro in the year of Alip 1555, more precisely 1 Muharam in 1043 H or July 8, 
1633. 
Every Javanese must have a weton because weton means the day of birth according 
to the day of the market. Market Day is a Javanese day consisting of only 5 days, namely 
Kliwon, Legi, Pahing, Pon, and Wage. These five days are commonly called Market days. 
It is called the market day because in the past each of these names was used as a name to 
determine the opening of the market for traders, so that on the day it was set a market 
there would be many visits by traders to sell their goods, and there were very many buyers 
who visited and shopped in the market. When revealed from ancestors in ancient times, 
the mention of the name of the 5 days of the market was taken from the name of 5 spirits. 
The names of the spirits include Batara Legi, Batara Paing, Batara Pon, Batara Wage, and 
Batara Kliwon. These five spirits are the main part of the human soul which has become