The study of dialectal maps has a long history in Japan. A Language Research Commission established by the Ministry of Education published two works at the beginning of the century, Phonetic Dialect Atlas (29 maps) in 1905 and Grammatical Dialect Atlas (37 maps) in 1906. Although based on materials gathered by the correspondence method, these polychromatic maps have not lost their scientific value. Further work on a linguistic atlas was, however, interrupted by the Kantô earthquake of 1923, when all the materials were destroyed.
A new survey aimed at establishing the Linguistic Atlas of Japan was started in 1955. The proposed aims were to determine the process of linguistic changes by the study of the dialectal distribution and to provide a tool to push the historical study of the language along new lines. In particular, the purpose of the investigation was to clarify the following points:
(1) the basis and formation of Modern Standard Japanese,
(2) geographical differences in Japanese and their development,
(3) the historical development of various dialects.
It can be said that this investigation produced the first reliable results of a nationwide linguistic survey.
After a two-year preparatory survey, the main survey was started in 1957 in the following way: one linguist was chosen for each of the 46 prefectures of Japan (in two cases, though, more were used), and these team workers used a detailed questionnaire provided by the National Language Research Institute to secure uniformity in the survey. A total of 285 questions were asked, mainly pertaining to the lexical field (nouns, verbs and adjectives), but with a few phonological and grammatical items. The number of localities was 2,400, or approximately one for every 150 square kilometers or one for 40,000 inhabitants. A male subject born before 1903 and native of the locality was chosen as the informant.
During the survey, the general direction and analysis of results was assured by the Dialect Section of the Institute, composed of the following members: SIBATA Takesi, NOMOTO Kikuo, UEMURA Yukio, TOKUGAWA Munemasa, KATÔ Masanobu, HONDÔ Hirosi, SATÔ Ryôiti and TAKADA Makoto. The work was done in cooperation with the above-mentioned local team workers and with a specialist in linguistic geography, Father Willem A. GROOTAERS.
The printing of the Atlas began in 1966 at the Printing Bureau, Ministry of Finance and was completed in 1974. Each part of the Atlas contains 50 maps, an introductory map, and an appended explanatory brochure. Each of the 50 maps is 5875 square centimeters in size and is printed in one to eight colors. The content of each of the parts is as follows:
Part 1. Phonology Maps and Adjective Maps
Part 2. Verb Maps
Part 3. Noun Maps: People and Amusements
Part 4. Noun Maps: Everyday Life, Agriculture, Agricultural Products, etc.
Part 5. Noun Maps: Animals and Plants
Part 6. Noun Maps: Almanacs, Weather, Nature, etc.
Each plate contains information concerning the vocabulary used to express specific meanings, the meaning of specific linguistic forms in various dialects, the pronunciation of specific linguistic forms (in detail), and combination maps illustrating the information from several separate maps.