(Japanese: イッシュ地方 Isshu-chihō) is a region of the Pokémon world, the setting of the Generation V Pokémon games Pokémon Black and White.
Little is known about Isshu at present, aside from the fact that it is located far away from all four past main series regions Kanto, Johto, Hoenn, and Sinnoh. Unlike the previous four, which are based on parts of real-world Japan, Isshu has been stated by Junichi Masuda to have been based on New York City in the United States of America.
Masuda has also revealed that Isshu's name comes from the kanji 一種 isshu, meaning "one variety". The reason for this choice was to express that even though the region has great diversity in species and race, when seen from a distance they are all the same as living creatures, and may also be based on the motto of the United States, e pluribus unum, Latin for "from many, one".
Like prior regions, while its general layout and coastline is based upon a real-world location, unlike New York, Isshu is not simply one large city. While the largest of its cities, Hiun City, is based upon the densely-populated area of Lower Manhattan, to the north, rather than more cityscape, a vast desert lies. To the west and east, there are great mountains, as well, and rather than urban areas, aside from Hiun, most of Isshu is decidedly rural.
Motor vehicles are present in one scan, while CoroCoro's article on the games indicate that Isshu may be more technologically advanced than the previous four regions. Another scan, however, shows wooden railroad tracks, a stark contrast to the ultra-modern Magnet Train present in Kanto and Johto.
Unlike the past four regions, which used the same numbered route system (notably with gaps between 48 and 101 and 134 and 201), Isshu's routes again start from 1, indicating that it is under an entirely different jurisdiction than the other four.
Version-exclusive locations, Black City and White Forest, are a first in Isshu, with Black City taking the place of White Forest in Black Version, and vice versa in White Version.