Archaeologists have found numerous
Kofun period remains at numerous locations in what is now Saiwai-ku, indicating a long period of human settlement. Under the
Nara period Ritsuryō system, it became part of Tachibana District
Musashi Province. In the
Edo period, it was administered as
tenryō territory controlled directly by the
Tokugawa shogunate, but administered through various
hatamoto, and was the center of a prosperous farming area adjacent to
Kawasaki-juku, a
post station on the
Tokaido highway connecting
Edo with
Kyoto. After the
Meiji Restoration, the area urbanized due to its proximity to
Kawasaki Station on the
Tokaido Main Line. Saiwai Village within Tachibana District in the new
Kanagawa Prefecture was created on April 1, 1889, through the merger of eight smaller hamlets. In the early twentieth century, the area was dominated by factories; notably Meiji Sugar and Toshiba. The area was largely destroyed by the
Great Kanto earthquake of 1923, but was soon rebuilt. The area was annexed by the neighboring city of Kawasaki in two stages in 1927 and in 1937. The area was heavily damaged by American bombing during
World War II. Saiwai Ward was established with the division of Kawasaki into wards on April 1, 1972. ==Economy==