Wat Phon Chai is a religious place located on the banks of the Man River in the town of Dan Sai. The important religious location of the temple is on a high hill. Which in the dialect is called "Phon", so called "Wat Phon", when the Phon Chai Temple was built, there was no clear evidence. Local historians speculate that it should be built at the same time as the construction of Phra That Si Song Rak during the year 2103-06 as the residence of monks who attended the Phra That Si Song Rak ceremony [9]. With art historians stating that the temple has a chedi with an architectural style similar to Phra That Si Song Rak. But smaller and more erect, which was likely to be built around or a little after the creation of Phra That Si Song Rak. Villagers believe that the mound of the land that was built as Phon Chai Temple was caused by the soil of the Naga Ruins. Which in the era of the Naga Buddha used to offer this area for the Lord Buddha to stay Along with the 500 disciples before, the Naga's mouth of the dragon became a small mound. Dan Sai people called this mound "Phon". Later temples and religion were built on the mound and named them. It is auspicious that "Wat Phon Chai" Above the mound of Wat Phon Chai, there is Viharn Luang, the largest and most important building of the temple. It is a building in the vernacular architectural style influenced by the Lan Xang architectural style. Facing south towards the Man River and the Dan Sai community. It was originally a vihara, a wooden pillar hall, but has been continuously renovated. The upper part is shingle with clay tiles. The lower part is a brick wall. With window Inside a large stucco Buddha image, the villagers call it “Luang Pho Phra Chao Yai” is a Buddha image in the Mara Wichai posture and gilded with a lap width of 79 inches. Local craftsmanship Around the 22-23 Buddhist century, it is assumed that it may have been built along with the construction of Phon Chai Temple. On the floor of Viharn Luang, on the back to the left of the Chukchi base, the Buddha image is attached to the wall with a hole-like hole, approximately 40 cm in diameter and about 1 m deep. Nun Sumngklo, Assistant Abbot of Phon Chai Temple It was made known that the making of this naga hole or hole was a replacement for the original serpent hole located behind the right side of the Chukchi base that was closed about 30 years ago. The original Naga hole was the same size as the current hole. The hole has been on the side of the Chukchi base for a long time. It is assumed that since, along with the construction of the royal vihara Used to drop a dried coconut into a hole It appears that the dried coconut appeared to float in the Manan River around Wang Wen Pier, which is opposite the Grand Viharn to the east. Dan Sai people believe that it is the up and down of the serpent from the Manan River who comes to take care of the Great God. In the past, there is still a story that during the days the monks often appear mud or water on the base of Chukchi and on the lap of the Great God. Some say it is a mark similar to the mark of a serpent. The mud or water that appears above is believed to be the mud attached to the serpent who came to worship and take care of Lord Yai Wat Phon Chai. Caused by the mouth of the Naga Ruins from the modern era as well Later, provost Sumon Wuttikorn (Reverend Grandfather Yai) Former Abbot of Phon Chai Temple Has closed the hole of the dragon Because they did not want the serpent to take mud into the viharn But after closing the hole, Phon Chai Temple was not prosperous. However, it deteriorated, causing the Naga in 1993 to take shape, Grandma Sompong Chaamontree, villagers in Den Sai Subdistrict, along with saying that why they closed the path of Naga Because the dragon was unable to take care of the great god Covering the holes of a serpent is like closing a temple. After the serpent took over, the villagers' monks and the temple committee agreed to open the hole behind the Great God once again. By shifting to the left side of the Chukchi base For the serpent to take care of the Great God Since then, Phon Chai Temple has flourished and is known to both Thai and foreigners as the venue for the world-famous Boon Luang festivities and Phi Ta Khon performances. From the interpretation of historical and folklore evidence, it was found that the word "Naga" appeared in various legends or myths, sometimes not referring to animals. Southeast Asia Which had its own religious belief system before, namely the cult of serpent worship or the serpent.Therefore, the mythical tales about the serpent in the Barren River basin may be related to the indigenous people who worship the serpent or the serpent. Then later it was changed to accept the Buddhist motto later. But still praised the naga to continue to protect and protect Buddhism The belief in the dragon root at Phon Chai Temple It is evident that the location of Phon Chai Temple has created a Buddhist temple overlaid on the sacred ground of traditional beliefs. Explanation of the coming of the Lord Buddha and his disciples, and the serpent gave up the mound of the hole at the mouth of the hole as his residence. This reflected that Buddhism was enshrined in the area of ​​Wat Phon Chai, replacing the sacred area of ​​the serpent beliefs of the traditional indigenous people. And it is the acceptance of Buddhism instead of the traditional beliefs about Naga of the people in this barren river basin.