General Introduction to Aichi Prefecture  


Topography and Climate

Aichi Prefecture is located in central Japan facing the Pacific Ocean, resulting in attractive natural features such as Ise Bay and Mikawa Bay. The prefecture has four adjacent neighbors: Mie Prefecture, Nagano Prefecture, Shizuoka Prefecture, and Gifu Prefecture. Ranked 26th in Japan for its land surface area, Aichi covers a total of 5,165 km2, thus accounting for 1.4% of the country’s total land mass.

The Kiso River forms the prefecture’s western border and flows through the Nobi Plain, the second largest plain in the country. The hilly Owari region lies to the east and extends south to form the Chita Peninsula. The Yahagi River runs through central Aichi, with the Mikawa Highlands lying to the north and the vast Okazaki Plain situated to the south. In the eastern region lies the Toyogawa River, with the Shitara Highlands and Yana/Yumihari Highlands located to the north and the Toyohashi Plain spreading to the south. The Atsumi Peninsula then extends from the Toyohashi Plain.

The Pacific current favors a generally mild climate in this part of the country. However, compared with the neighboring cities of Okazaki and Toyohashi, the summer heat in Nagoya is remarkably severe. The annual rain precipitation is more abundant closer to the mountains than in the plains or peninsulas.


In ancient times, the region that accounts for present-day Aichi was formed by three distinct independent domains, namely Owari, Mikawa, and Ho. The region was then united into two domains, Owari and Mikawa, as the result of the Great Reform of Taika in 645. Owari and Mikawa continued to prosper for centuries throughout the Edo period (1603 - 1868).

Following the abolition of feudal domains in 1871, Owari and Mikawa became Nagoya Prefecture and Nukata Prefecture respectively. In April 1872, Nagoya Prefecture was renamed Aichi Prefecture, and in November of the same year, Nukata Prefecture was merged into Aichi Prefecture. Thus was born present-day Aichi Prefecture, a unification of the historic Owari and Mikawa domains.

At that time, there were more than 2,900 towns and villages in the prefecture. However, municipal merger movements in the 19th and 20th centuries drastically reduced this number, making it 88 in 1970. The number remained unchanged for about 30 years until 2003 when 15 municipal mergers took place under another nationwide merger movement. As of February 1, 2011, the prefecture comprises 57 municipalities (37 cities, 18 towns, 2 villages).

Origins of the Name of Aichi

The name of Aichi originated in the mind of a gifted poet named Takechi Kuroto, who composed the following poem compiled in the Manyoshu (“A Collection of Ten Thousand Leaves” [ca. 750]) Volume III. The poem reads, “A caw of crane leaves an echo in the field of Ayuchigata; I wonder if the crane came to pick up fish in the tideland.” In this poem, Kuroto sings about a tidal place known as Ayuchi, which eventually became Aichi. The name Aichi was adopted as the name of the prefecture because the Prefectural Government was established in the center of then Aichi County.

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