The carousel "El Dorado" is Japan's oldest play machine and is a merry-go-round with a long history in the world.

Celebrities such as former US President Theodore Roosevelt, Marilyn Monroe, and Al Capone also boarded and were loved by New Yorkers.

[4] Since the parts were disjointed and the paint had peeled off, the operation started on April 3, 1971 after two years of restoration work under the guidance of experts at the time, such as Japanese carpenters specialized in wooden structures known as miyadaiku, art teachers, and electrical engineers.

[11] The drowning incident occurred on 15 August 2019 at the 'Fluffy Water Land' (ふわふわウォーターランド) attraction in Toshimaen, an amusement park that was located in Nerima, Tokyo.

[13] A young girl, referred to here as 'A', who was wearing a life jacket, was found floating beneath the play equipment and subsequently drowned.

[14] It was concluded that the girl had fallen into the water, slipped under the play equipment, and was unable to escape due to the buoyancy of her life jacket.

[15] In response to this incident, the Ministry of Economy, Trade and Industry established guidelines for the safety of water-based play equipment.

[19][13] These are professionally referred to as 'air membrane structure toys',[20] which float on the water surface by inflating them with air.

[19] The planning and design of the "Fluffy Water Land" were carried out independently by Toshimaen, and the toys were procured from a manufacturer in China.

[21] The life jackets provided at the "Fluffy Water Land" were solid-structured, using expanded polystyrene for buoyancy, and were shaped like a waistcoat.

[29] According to pool patrons who witnessed A being pulled out of the water, she was pale and limp when she was rescued, and a person believed to be C was screaming.

The "Fluffy Water Land" remained closed in 2020, leading up to the closure of Toshimaen itself on 31 August of the same year.

[13] On 8 May 2020, the bereaved family members B and C of the deceased A filed a civil lawsuit in the Tokyo District Court, claiming that A's death was due to a lack of thorough safety management.

[30] They sought a total of approximately ¥ 75 million (£377,600) in damages from Toshimaen, its parent company Seibu Railway, the contractor in charge of surveillance, and the manufacturer and installer of the play equipment.

Toshimaen officials attended A's funeral, but did not participate in the condolence visit and did not comply with the out-of-court dispute resolution procedure.

"[15] The pool management company responded to an NHK interview immediately after the accident, stating that they had not anticipated that someone would enter under the play equipment.

[31] The first oral argument took place on 14 September 2020, but all the defendants indicated a willingness to contest the case and asked for the plaintiff's claim to be dismissed.