[1] It was completed in 1997, despite formal objections from the local Ainu people dating as early as 1987.

These two farmers of Ainu descent claimed the government had illegally seized their land in February 1989.

[2] They believed that the expropriation of their land to build dam violated their rights as Ainu for the protection of their cultural heritage because the dam construction would destroy sacred sites and ritual grounds had not been adequately considered in the forced taking of their lands.

In a landmark decision by the Sapporo District Court,[3] Chief Judge Kazuo Ichimiya stated that the Ainu people had established a unique culture in Hokkaido before the arrival of the Japanese and therefore had rights that should have given consideration under Article 13 of Japan's Constitution, which protects the rights of the individual, and in the International Covenant on Civil and Political Rights.

However, the decision included extensive fact-finding that underscored the long history of the oppression of the Ainu people by Japan's ethnic majority, referred to as "Wajin" in the case and discussions about the case.