The police rescue operation on the final day of the standoff was the first marathon live television broadcast in Japan, lasting 10 hours and 40 minutes.

The lodge was a natural fortress, solidly constructed of thick concrete on a steep hillside with only one entrance, which, along with their guns, enabled the hostage-takers to keep police at a distance.

Attempting to conceal themselves from the police, a core group of radicals from the United Red Army (URA) retreated to a compound in Gunma Prefecture during the winter of 1972.

The Keihin Anti-Security Treaty Joint Struggle Group, led by Hiroko Nagata and Hiroshi Sakaguchi, raided a gun shop in Mooka (Tochigi Prefecture) on February 17, acquiring 9 shotguns, 1 rifle, 1 airgun, and 2300 rounds of ammunition.

[2] Panicked by the prompt response of the police, most raiders escaped by car but two were left behind; once arrested, they identified the culprits, resulting in Nagata, Sakaguchi, and the others being placed on the wanted list.

Separately, the Red Army Faction led by Tsuneo Mori, and including Kunio Bandō (who is still at large), carried out a series of robberies—4 banks, 3 post offices, and an elementary school—over the period February 22 to July 23, 1971 (referred to by police as "Operation M", for "money").

[3] The police launched a nationwide manhunt, making it impossible for perpetrators to hide, even in distant cities such as Sapporo and Kyoto; both groups decided to converge in the mountainous area of NW Gunma Prefecture.

Separately, the Red Army Faction left the cities and set up an agitpunkt in Yamanashi Prefecture (the Niikura Base).

On 18 December, radio news announced that Shibano Haruhiko [ja], a member of the Keihin group still in the Tokyo area, had been shot to death during an assault on a police station in Itabashi.

Without hope of outside help or escape, in late 1971, the leaders of the two factions, Mori and Nagata, planned a "annihilation operation" (殲滅戦, senmetsusen) which required an ideological review process of criticism and self-criticism of all members.

[4][page needed] It was at the Gunma compound, on the second week of February 1972, that URA chairman Tsuneo Mori and vice-chairman Hiroko Nagata initiated a violent purge of the group.

Five others, armed with rifles and shotguns, managed to escape, fleeing on foot through the mountains towards the community of Karuizawa in nearby Nagano Prefecture.

A crane equipped with a wrecking ball and an armored driver's compartment was positioned near the building and police armed themselves with ladders, heavy mallets, and chainsaws.

On 24 June 2013, the Supreme Court of Japan rejected an appeal from Sakaguchi for a retrial, leaving him on death row awaiting execution.

Bandō later is believed to have assisted in the hijacking of Japan Airlines Flight 472 from Paris to Tokyo in 1977, forcing the jet to land in Dhaka.

Quotations from her initial press conference were twisted out of context to make it sound like she had become friends with her captors, and her presence at the funerals for the two officers was denounced in the weeklies as a "hypocrite" shedding "crocodile tears.

[22] The incident, along with the Lod Airport massacre which occurred several months later and several hijackings, contributed to an intense social backlash amongst the Japanese population against radical student leftist groups.