Wat Jan, or the Monastery of the Moon (1), was located centrally on the city island in the Pratu Chai Sub-district. The original temple was situated just south of Wat Maha That and east of Wat Nok on the edge of the Ayutthaya Historical Park.
The temple stood on the west bank of Khlong Pratu Khao Pluak. The latter is a defunct north-south running canal situated on the Ayutthaya city island. The canal was a shortcut in the oxbow of the old Lopburi River with its beginning at the Khao Pluak Watergate near Wat Racha Pradit Sathan and its mouth at the Chinese Watergate in front of Wat Khun Phrom. This canal was called Khlong Pratu Jin, south of the Chikun Bridge.
The construction of Chikun Road has buried the temple area, and only a restored brick base of a small chedi stands as a last witness of the past. The base of the chedi standing on a square platform is octagonal but redented at the inter-cardinal directions. A part of the stucco work which once covered the entire chedi still can be seen.
The site is found on a 19th-century map (2), and on the Fine Arts Department maps since 1974.
Its historical background and period of construction are not known.
The site is in geographical coordinates: 14° 21' 21.78" N, 100° 34' 6.88" E.
Footnotes:
(1) The word "Jan" [transliterated: Chan] could also be translated as "sandalwood", written commonly in Thai as จันทน์. On many occasions, Thai monasteries were called after (medicinal) trees or flowers. Sandalwood is one of the popular scents used for incense. As all the Fine Arts Department maps show จันทร์, I kept the correct translation, being "moon".
(2) The locations of Wat Nok and Wat Lat are not correctly mapped on the mid-19th century map, given the geographical positions seen today. The indicated position of Wat Jan on the detail is derived from the fact that the temple is positioned opposite Wat Lat. I have categorised this monastery as a restored ruin because there is still some brickwork, which the Fine Arts Department 3rd Region has restored.