The Local Directory of 1940 (ทำเนียบท้องที่ พุทธศักราช 2483) - one of the books I was able to scan from the Pridi Library - gives the number of administrative villages for every subdistrict, thus it gives me a complete list of all the Tambon in that year. As I suspect that not all the Tambon creations and dissolvements have been recording in the Royal Gazette, and the
creation of more than 1000 Tambon in one year always has been very suspicious, this list should be great to consolidate my Tambon data.
Working through all
300 pages will take me several months, yet as a proof of concept I have processed the Tambon list of
Krabi, simply as that province is listed first as being the first in Thai alphabet. And with 534 Tambon today its a relatively small province.
In 1940, Krabi had 39 Tambon and 283 Muban in four districts, compared with 8 district, 53 Tambon and 389 Muban today. All of the Tambon listed in 1940 could be directly matched to a present-day one with the same name, so none was dissolved in the meantime. Only
Na Nuea (ตำบลนาเหนือ) in Ao Luek isn't found directly, as it is listed as Pak Lao (ตำบลปากลาว) in the book - but corrected as Na Nuea in the appendix. Actually, the Tambon was renamed in 1940 while the book was compiled [
Gazette].
Checking the other way round, there is only one Tambon not present in the 1940 list which has no Royal Gazette announcement on it being created -
Sai Thai (ตำบลไสไทย) in Mueang district. It was mentioned in a Gazette announcement in 1952, so it was apparently created sometime in the 1940s. And since the 1937 census included a book with the population for each Tambon (more on that later), there is one more Tambon which changed in these years -
Khao Din was renamed from Yan Sao, while it was reassigned from Surat Thani in 1937 it is already included in Krabi.
Krabi was an easy pick as a first step to work through that list, the
XML with the data will slowly grow later. Sadly, there were none of the 1000 Tambon in this province, so it doesn't answer yet what was that announcement all about. Also, there were no difficulties like dissolved or renamed Tambon without any official records I could find so far. When I am running into such problems I'll certainly write about them