The locale is a local region of the board suitably chosen for counting stones, intersections or points conveniently.
This definition is taken from Joseki Volume 2 Strategy, page 12. While this could be the first appearance in 2011 in printing, Robert Jasiek has used the term for several years. Usage as an unnamed concept is quite some years older. In many combinatorial game theory discussions but also in ordinary endgame calculations, implicitly the concept has been and is applied regularly by everybody.
Anonymous: the concept has been explicitly referred to as region for more than 20 years.
RobertJasiek: 1) I have not witnessed this. 2) Calling it a region without further specification of its nature and the considered intersections does not show explicit understanding of the concept.
Anonymous: Contrary to your impression, region has been used explicitly in the local sense in CGT and other discussions and publications at least since Mathematical Go, in which it appears on p. 155. It also is used a number of times on the pages Temperature and Chrisd/Computer Go Improvements. I can search other references, but these should be enough.
RobertJasiek: Chrisd/Computer Go Improvements only speaks of surrounded region preferably by Benson-alive stones, but a locale need not be surrounded and need not be given by Benson-alive stones. Temperature speaks of local region in contrast to the environment so means a local endgame's region, but locale need not be a whole region of a local endgame. Mathematical Go Endgames, p. 155 speaks of region meaning empty nakade shapes, but locale need not be a nakade. Please provide evidence instead of irrelavent or unrelated uses of (local) region.
Anonymous: All of these examples are not irrelevant. The regions are "suitably chosen" for counting purposes. True, they use the term, region, instead of locale, but they are not implicitly using the concept of locale, as opposed to region.
RobertJasiek: They do not show an understanding of locale as a more specialised concept than local region. If their use can also be described by locale, it is only accidental. As it is accidental if somebody does not understand locale and therefore always considers a whole local region for calculating counts and so wastes very much time counting and recounting points on not changing intersections. In fact, it is a very frequent mistake of wasting time because of not understanding the difference between local region and locale.
Anonymous: In that case, do not say that they implicitly apply the concept. They do not say locale, they say region. Your definition of locale is more specific. Leave it at that.
RobertJasiek: Whenever some CGT tiny board part was shown in Mathematical Go Endgames or some research paper, or some player calculated something like hane-connect on only the played-on intersections, this has been implicit use of the concept of locale.
Anonymous: No, it has been the application of the more general concept of region. Locale, by your definition, is a kind of region. The more general concept is satisfactory in such instances, without depending on the specific concept of locale.
RobertJasiek: Since region is insufficient, the authors of such texts take great care to exactly show and mark only the counted parts.