Title: Naka-ku, Sakai
Content:  Naka-ku (中区) is a ward of the city of Sakai in Osaka Prefecture, Japan. The ward has an area of 17.94 km² and a population of 121,377. The population density is 6,766 per square kilometer. The name means "Central Ward." The wards of Sakai were established when Sakai became a city designated by government ordinance on April 1, 2006.
Title: Naka, Ibaraki
Content:  Naka is located in north-central Ibaraki Prefecture, with the Naka River and Kuji River flowing through the city.
Title: Naka-ku, Yokohama
Content:  Naka Ward is located in eastern Kanagawa Prefecture, and east of the geographic center of the city of Yokohama. Its name means "middle ward." In the low-lying Northern district, commonly referred to as Kannai, it hosts the Yokohama city hall and the headquarters of the Kanagawa prefectural government. The central part of the ward includes elevated ground; this area, known as Yamate, has long been a residential area. Along the shore lies reclaimed land upon which port facilities, part of the Minato Mirai 21 complex, and Yamashita Park were built. To the south are the piers, oil refineries and the central port of Yokohama. The Nakamura River, a branch of the Ōoka River, cuts across the northern part of the ward. The northernmost and southernmost points are upland.
Title: Naka-ku, Yokohama
Content:  Naka-ku (中区) is one of the 18 wards of the city of Yokohama in Kanagawa Prefecture, Japan. In 2010, the ward had an estimated population of 146,563 and a population density of 7,080 persons per km². The total area was 20.86 km².
Title: Naka-ku, Nagoya
Content:  Naka Ward is located in the center of Nagoya city. Largely hemmed in by Sakura-dōri (桜通り), Ōtsu-dōri (大津通り), Fushimi-dōri (伏見通り) and Tsurumai-dōri (鶴舞通り), it contains the main shopping area of Sakae which includes a massive air-conditioned 5 square-kilometer underground mall and the 'after-five' semi-red light districts of Nishiki and Shin-sakae.
Title: Naka-ku, Hamamatsu
Content:  Naka-ku (中区) is one of seven wards of Hamamatsu, Shizuoka, Japan, located in the central part of the city. It encompasses the site of Hamamatsu Castle and Hamamatsu Station, the central business district and a number of high density residential areas. Although its area is the smallest of the seven wards of Hamamatsu, it has the largest population. It is bordered by Higashi-ku, Kita-ku, Minami-ku, and Nishi-ku. Naka-ku was created on April 1, 2007 when Hamamatsu became a city designated by government ordinance (a "designated city").
Title: Naka, Tokushima
Content:  Naka (那賀町) is a town located in Naka District, Tokushima Prefecture, Japan. It was founded on March 1, 2005 from the merger of the towns of Aioi, Kaminaka and Wajiki, and the villages of Kisawa and Kito, all from Naka District. As of June 1, 2019 the town has an estimated population of 7,549 and a density of 10.9 persons per km². The total area is 694.98 km².
Title: N/naka
Content:  n/naka is a two-Michelin-star modern kaiseki restaurant located in Los Angeles, founded by chef Niki Nakayama. The name is a portmanteau of Nakayama's first and last name. In 2019, n/naka was named to Food & Wine's 30 best restaurants in the world.
Title: Nakaizu, Shizuoka
Content:  Nakaizu (中伊豆町) was a town located in Tagata District, Shizuoka Prefecture, Japan, in central Izu Peninsula. As of March 1, 2004, final population data before the amalgamation, the town had an estimated population of 8,457 and a density of 77.03 persons per km². The total area was 110.02 km². On April 1, 2004, Nakaizu, along with the towns of Amagiyugashima, Shuzenji and Toi (all from Tagata District), was merged to create the city of Izu. Nakaizu, located in the Izu-Kogen highlands of central Izu Peninsula was noted for its production of wasabi and shiitake.
Title: Naka-ku, Nagoya
Content:  Naka Ward (中区) is one of the 16 wards of the city of Nagoya in Aichi Prefecture, Japan. As of 1 October 2019, the ward has an estimated population of 90,918 and a population density of 9,693 persons per km². The total area is 9.38 km².

Question: What is Naka-ku the capital of?
Answer: Yokohama.