Wat Krachai is a restored ruin located off the main island, on the western side of Ayutthaya, in the Pak Kran Sub-district. The monastery was named after the 'Boesenbergia rotunda', commonly known as Chinese keys, fingerroot, lesser galangal or Chinese ginger, a medicinal and culinary herb from China and Southeast Asia. In Thailand, it is cultivated for culinary and medicinal purposes.
The site is sometimes called Wat Krasai, but this is due to a misreading/writing of the consonants (ซ and ข). Many temples are named after essential trees or plants this monastery is no exception.
There must have been a canal in its vicinity, as Ayutthaya was known for its water transportation system, but the waterway is today defunct. The monastery can be reached via Road No 3409 and can be seen from Road No 347.
Wat Krachai is in the middle of the rice fields, where periodic flooding is common and has remained largely secluded until recently. The temple's establishment date is unknown, but Wat Krachai is assumed to date to the early Ayutthaya period (1351 - 1488 CE). The first monastic buildings were constructed on a manufactured mound to avoid flooding. Very few ancient objects from that period were found.
In the middle Ayutthaya period (1488- 629 CE), the site was restored and enlarged. Wat Krachai received a tall stupa in a similar style as Wat Sam Pluem, Wat Suwannawat, Wat Nang Kham, Wat Jong Krom, Wat Langkha Khao, and Wat Phra Ram (Thung Khwan). All were constructed with brick and mortar, having an octagonal base, a bell-shaped dome and an octagonal-shaped harmika. In front of the principal chedi of Wat Krachai, a vihara facing east was constructed. The principal chedi was surrounded by four auxiliary chedis forming a quincunx. The whole was built on an east-west axis.