The defendants in a controversial case involving the legality of US bases in Japan have filed for a retrial.

The trial came to be known as the “Sunagawa Case” as it involved protesters who entered a US airbase in the Tokyo suburb Sunagawa.

The protestors were convicted of illegal entry in 1957 in a ruling that found the US military presence in Japan did not violate the country’s peace constitution.

Four defendants today filed to reopen the case on the grounds the ruling was prejudiced.

They say US documents now show that Japan’s chief justice at the time leaked details on the case to the US.

The defendants say the court should have dismissed the case, and are demanding a retrial.

They also say Japan shouldn’t proceed with its plan to ease restrictions on its own military based on an invalid ruling.

Prime Minister Shinzo Abe wants to reinterpret Japan’s constitution to allow its military to help defend allies under attack.