Wat Khian is a restored temple ruin situated on Ayutthaya’s city island in Tha Wasukri Sub-district. This temple ruin can be accessed via U-Thong Road, not far from the Hua Ro market and Wat Khun Saen. The site is at present part of the Wat Khian Municipal School. Schools in Central Thailand are often found in the vicinity of monasteries as the latter once served as education centres.
Wat Khian stood on the south bank of the old Lopburi River, present Khlong Mueang, within the old city walls. Wat Khun Saen stood on its north Wat Tha Sai was west, Wat Ratcha Phruek on its east and Wat Wihan Thong on the opposite river bank.
A new pavilion has been constructed on top of the foundations of the old monastic structure. The pavilion is called Wihan Luang Pho Khao, referring to the white main Buddha image and the three minor Buddha images sheltered. The vihara faces north towards the Lopburi River.
Two minor chedis from the late Ayutthaya period remain in front of the pavilion and on the edge of the U-Thong Road.
Maps
I believe Wat Khian shows on Engelbert Kaempfer’s sketch. Kaempfer was a medical doctor working for the Dutch VOC (Verenigde Oost-Indische Compagnie) who surveyed the city of Ayutthaya in June 1690 CE. Though the sketch is a bit unclear in that area, there are two marks of temples at a short distance of each other. A road is running to the south of both temples (today, U-Thong Road is to their north), which let us assume that the city wall was the northern limit of the temple area.
Wat Khian is indicated on a 19th-century map in between Wat Tha Sai and Wat Khun Saen. The map suggests no existence of a chedi nor a prang. It shows a second denomination for this temple being Wat Sihra (วัดสีหรา), referring to a lion or king of lions. As thus, this temple could have been formerly called the Monastery of the Lion. Between Wat Khun Saen and Wat Khian, the map displays an unnamed fort, which should be Pom Jampaphon from the Description of Ayutthaya. This fort is found on no other maps.
Phraya Boran Ratchathanin's map of 1926 CE has Wat Khian exactly between Wat Tha Sai and Wat Khun Saen and closer to the latter.
The brickwork of Wat Khian is in geographical coordinates: 14° 21' 52.27" N 100° 34' 12.47" E.
Footnotes:
(1) Khian (เขียน), translated meaning "writing", was sometimes given as a nickname to a person in Siam. Monasteries were often named after their establishers or sponsors. The monastery here could eventually be named after its sponsor.
(2) I believe that the mid-19th century map has mainly been drafted based on the old documents (Description of Ayutthaya). We can see the position of the fort was all but strategic. I have doubts about the earlier existence of this fort.
(3) The main Buddha image of a temple is orientated in the first place towards a waterway and secondly to the East. Still, the water, in general, has priority over the direction. The combination of the two is, of course, the ultimate.