What an ikkensha is
An ikkensha is a shrine building one bay wide at the front. A bay, ken, is the space between two posts: two posts across the front make a one-bay shrine, four posts a three-bay shrine, and so on.
Japanese records attach the term to the roof or plan type. The main hall of Umeda Shrine in Kameoka, Kyoto Prefecture, built in 1338 and designated an Important Cultural Property, is recorded as a one-bay nagare-zukuri with cypress-bark roofing, and so is the Sanbo Kojin shrine at Kangiin in Kumagaya, Saitama Prefecture, from 1787. The prefix combines with kasuga-zukuri and shinmei-zukuri too, and a household shrine of 1888 in Fukushima is recorded simply as a one-bay gabled shrine.
The JAANUS dictionary describes the ikkensha as a small one-bay sanctuary, most often associated with the Kasuga form. One-bay shrines without front steps, with a projecting shelf instead, are called misedana-zukuri.
Reading the records, and what to look for
One-bay nagare-zukuri is two pieces of information, not a single style name: the bay count and the roof form. A three-bay nagare-zukuri is simply the same roof over a hall three bays wide.
On site, stand in front and count the posts of the hall itself, not the posts of the front canopy, which stand separately in front of it. Two posts across the hall means a one-bay shrine.
Because they are small, one-bay shrines are common among the subsidiary shrines beside or behind a main hall, and many are housed in protective sheds. Some, like Umeda Shrine, are the main hall itself. In writing, copy the record's structure field as given.
References
- JAANUS (Japanese Architecture and Art Net Users System): ikkensha-zukuri
- https://projects.mcah.columbia.edu/jaanus/record/ikkenshazukuri
- Agency for Cultural Affairs, Database of National Cultural Properties: Umeda Shrine Main Hall
- https://kunishitei.bunka.go.jp/bsys/maindetails/102/1981
- Agency for Cultural Affairs, Database of National Cultural Properties: Kangiin Sanbo Kojin Shrine
- https://kunishitei.bunka.go.jp/heritage/detail/101/00011452
- Agency for Cultural Affairs, Database of National Cultural Properties: Heishi Family Residence Household Shrine
- https://kunishitei.bunka.go.jp/heritage/detail/101/00011252
Last verified: 2026.10.04