is a city located in Ibaraki Prefecture, Japan. , the city had an estimated population of 59,314 in 21,168 households and a population density of 480 persons per km<sup>2</sup>. The percentage of the population aged over 65 was 38.8%. The total area of the city is . The city has a large expatriate population from Brazil.
Jà Âsà  is located in southwestern Ibaraki Prefecture, approximately 50 kilometers north of central Tokyo and 70 kilometers from the prefectural capital at Mito. Most of the city is flat, with an average elevation of 10 to 20 meters above sea level. The Kinugawa River flows through the city.
Chiba Prefecture
Ibaraki Prefecture
Jà Âsà  has a Humid continental climate (Köppen Cfa) characterized by warm summers and cool winters with light snowfall. The average annual temperature in Jà Âsà  is 14.2 ðC. The average annual rainfall is 1302 mm with September as the wettest month. The temperatures are highest on average in August, at around 26.2 ðC, and lowest in January, at around 3.1 ðC.
Per Japanese census data, the population of Jà Âsà  peaked around the year 2000 and has declined slightly since.
During the Edo period, the area was part of Shimà Âsa Province, and Mitsukaido village developed as a center for river transportation on the Kinugawa River. The town of Mitsukaidà  was established within Toyoda District with the creation of the modern municipalities system on April 1, 1889. The area was transferred to Yà «ki District in 1894. On July 10, 1954, Mitsukaidà  merged with the villages of Sugawara, Ohanawa, Mitsuma, Goka, Ono and Sakate, and was elevated to city status. It further annexed the villages of Sugao and Uchimoriya on April 1, 1956.
On January 1, 2006, Mitsukaidà  absorbed the neighboring town of Ishige, Yà «ki District, Ibaraki and officially changed their name to Jà Âsà Â. The area suffered much damage from flooding of the Kinugawa River due to heavy rains in September 2015.
Jà Âsà  has a mayor-council form of government with a directly elected mayor and a unicameral city council of 22 members. Jà Âsà Â, together with neighboring Yachiyo, contributes two members to the Ibaraki Prefectural Assembly. In terms of national politics, the city is part of Ibaraki 7th district of the lower house of the Diet of Japan.
Jà Âsà  has a mixed economy, with three large industrial parks; however, 50% of the city's area is farmland.
Jà Âsà  has 14 public elementary schools and five public middle schools operated by the city government, and three public high schools operated by the Ibaraki Prefectural Board of Education.
In additional there are two Brazilian schools: Escola e Creche Grupo Opção and Escola Taiyo One more Brazilian primary school (UBEK â Unidade Brasileira de Ensino Kanto) is now closed
Kantà  Railway Jà Âsà  Line