Question: What district of Japan does Toyoko Tokiwa cover in his book about Yokohama after World War 2?

Context paragraphs:
Heidelberg-Südstadt: Heidelberg-Südstadt ("South Town") is a district of the city of Heidelberg in Baden-Württemberg, Germany.  It is a relatively young district and was established after World War 2, by extending the Weststadt district to the south, and the Rohrbach district to the north.  Today, it houses about 4,400 citizens (including about 600 people not registered as residentials of the suburb).  Südstadt is the second-smallest district of Heidelberg by population, after Schlierbach.

Graves Gladney: James Francis Graves Gladney (1907–1976) was an illustrator known for his cover paintings for Street & Smith pulp magazines, especially "The Shadow".  He was a keen big game hunter and trap shooter and so, being a marksman, he served as a gunnery instructor in World War 2.  Posted to the 82nd Airborne Division, he made airborne landings during the Normandy invasion and Operation Market Garden.  He was, at his death, professor of fine arts at Washington University in St. Louis.  The original oil painting of his January 1941 cover for "The Shadow" was exhibited at the university's Olin Business School.  This was from his main period of activity for "The Shadow", producing all the covers from April 1939 to the end of 1941.

Type R ship: The Type R ship is a United States Maritime Administration (MARAD) designation for World War II refrigerated cargo ship, also called a reefer ship.  The R type ship was used in World War II, Korean War, Vietnam War and the Cold War.  Type R ships were used to transport perishable commodities which require temperature-controlled transportation, such as fruit, meat, fish, vegetables, dairy products and other foods.  The US Maritime Commission ordered 41 new refrigerated ships for the US Navy.  Because of the difficulty of building refrigerated ships only two were delivered in 1944, and just 26 were delivered in 1945 and the remainder in 1946–48.  The 41 R type ships were built in four groups.  Two of design types were modified type C1 ships and two were modified type C2 ships.  The United Fruit Company operated many of the R type ships in World War 2.  The type R2-S-BV1 became the US Navy Alstede-class stores ship and the type R1-M-AV3 became the US Navy Adria-class stores ship.

Yokohama Incident: The Yokohama Incident (横浜事件 , Yokohama Jiken ) took place in Imperial Japan during World War II.  Between 1943 and 1945, the Yokohama Special Higher Police arrested nearly three-dozen intellectuals for charges of attempting to revive the Communist Party.  Suspects included editors of the "Chuo Koron", "Kaizo", and "Nippon Hyoron" magazines.  Suspects were subjected to physical violence, and three died as a result of mistreatment.

Kamisseya: KamiSeya, a SIGINT base located approximately 12.15 kilometers from Yokohama in Japan, was built by Japanese forces and later used by the U.S. Navy in 1945 as a listening post to intercept Soviet and Chinese radio communications.  Since World War II, KamiSeya has been the home to U.S. Naval Air Facility (NAF) Atsugi, Japan.  The post was later transferred to Okinawa due to heavy electromagnetic interference from nearby Tokyo and Yokohama industrial areas.  In Okinawa, KamiSeya is known as the "Sobe base".

Yokohama Specie Bank: Yokohama Specie Bank (横浜正金銀行 , Yokohama Shōkin Ginkō ) was a Japanese bank founded in Yokohama, Japan in the year 1880.  Its assets were transferred to The Bank of Tokyo (now The Bank of Tokyo-Mitsubishi UFJ) in 1946.  The bank played a significant role in Japanese trade with China.  The original bank building is now the Kanagawa Prefectural Museum of Cultural History.  During the Second World War the bank controversially acted as the paymaster for the Imperial Japanese Army as it conquered parts of Asia.

Toyoko Tokiwa: Toyoko Tokiwa (常盤 とよ子 , Tokiwa Toyoko , 1930) is a Japanese photographer best known for her 1957 book of text and photographs "Kiken na Adabana" (危険な毒花 ), and particularly for its portrayal of the red-light district of post-occupation Yokohama, with US servicemen.

Sankei-en: Sankei-en (三溪園 , Sankei Garden ) is a traditional Japanese-style garden in Naka Ward, Yokohama, Japan, which opened in 1906.  Sankei-en was designed and built by Tomitaro Hara (原富太郎 ) (1868–1939), known by the pseudonym Sankei Hara, who was a silk trader.  Almost all of its buildings are historically significant structures bought by Hara himself in locations all over the country, among them Tokyo, Kyoto, Kamakura, Gifu Prefecture, and Wakayama prefecture.  Ten have been declared Important Cultural Property, and three more are Tangible Cultural Properties of Japan designated by the City of Yokohama.  Badly damaged during World War II, the garden was donated in 1953 to the City of Yokohama, which entrusted it to the Sankeien Hoshōkai Foundation (三溪園保勝会 , Sankeien Hoshōkai ) .  Sankei-en was then restored almost to its pre-war condition.

The Hoax of the Twentieth Century: The Hoax of the Twentieth Century: The Case Against the Presumed Extermination of European Jewry is a book by Northwestern University electrical engineering professor Arthur Butz.  First published in 1976 by Historical Review Press, it attempts to refute the idea of the Holocaust that Nazi Germany tried to exterminate millions of Jews using homicidal gas chambers during World War 2, and is influential in the Holocaust denial movement.  The book has been banned in Canada and is X-rated in Germany where it cannot be displayed or advertised.  It has been described as anti-semitic with Alan Davies calling it an "antisemitic classic".  In 2017, the online book seller Amazon.com removed the book, along with other holocaust-denying titles, from its US and UK sites.

Occupation of Japan: The Allied occupation of Japan at the end of World War II was led by General Douglas MacArthur, the Supreme Commander of the Allied Powers, with support from the British Commonwealth.  Unlike in the occupation of Germany, the Soviet Union was allowed little to no influence over Japan.  This foreign presence marked the only time in Japan's history that it had been occupied by a foreign power.  The country became a parliamentary democracy that recalled "New Deal" priorities of the 1930s by Roosevelt.  The occupation, codenamed Operation "Blacklist", was ended by the San Francisco Peace Treaty, signed on September 8, 1951, and effective from April 28, 1952, after which Japan's sovereigntywith the exception, until 1972, of the Ryukyu Islands was fully restored.

Supporting paragraphs: Toyoko Tokiwa Occupation of Japan
Answer: red-light district