G.I. Samurai (戦国自衛隊, Sengoku jieitai, Sengoku Self Defense Force) aka Time Slip, is a 1979 Japanese science fiction/action film focusing on the adventures of a modern-day Japan Ground Self-Defense Force (JGSDF) and Japan Maritime Self-Defense Force (JMSDF) team that accidentally travels in time to the Warring States period (戦国時代, Sengoku jidai). The film stars Sonny Chiba, one of the top male Japanese actors, and was based on a novel by Ryo Hanmura, a well-known writer of historical novels and science fiction. A remake was theatrically released in Japan in 2005 under the title Samurai Commando: Mission 1549.

During a defensive exercise, a wildly mixed group of Japanese SDF forces with a tank, an APC, a patrol boat and a helicopter suddenly find themselves stranded 400 years in the past through a sudden time slip effect and under attack by samurai forces. Their acting commanding officer, Second Lieutenant Yoshiaki Iba, befriends and joins forces with Nagao Kagetora, the war leader of lord Koizumi. Seeing the SDF weaponry in action, Kagetora persuades Iba to aid him in his struggle for supremacy in feudal Japan.

In the meantime, however, Iba finds himself faced with the desperation of his men who want to return to their own time. Some make contact with the locals – one, Private First Class Mimura, even finds himself a consort who keeps following him – whilst others freak out, running away in a desperate attempt to return home, or rebelling against rules and restrictions and try to live as pirates. Finally, his force shrunk from 21 men to 11, Iba manages to calm his troops by telling them that by fighting history and thus creating a time paradox they might be able to return home. Iba joins Kagetora and fights by his side.

Finally, Iba and the members face Takeda Shingen's forces in battle. But their trust in their advanced weaponry costs them dearly: Shingen's forces outmanoeuvre them at every turn, the soldiers lose all their vehicles and major weapons, and five of them die on the battlefield. In a desperate attempt, Iba forces his way to Shingen's command post and kills him in a sword duel.

As Iba and his remaining men go to join Kagetora in Kyoto, the latter is put under pressure by his family and the Shōgun Ashikaga Yoshiaki to get rid of Iba. Reluctantly conceding, Kagetora intercepts Iba's group at an old temple. But as Iba prepares to kill Kagetora for his betrayal, Kagetora shoots him. The other soldiers are killed by Kagetora's archers, and Mimura's consort delivers the fatal blow to her lover.

Kagetora remorsefully buries Iba and his men with honors. In the end, only one of the members, Private Mokichi Nemoto, survives, who had left the group to help a boy and his family, whose father had been killed.

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Initially, the producers approached the Japan Ground Self-Defense Force (JGSDF) for props and vehicles, but the army cut their support after reading that the soldiers went AWOL in the script. For that reason, old and sometimes out-dated equipment (like M3 submachine guns) had to be used. The tank featured in the movie was even built entirely from scratch.

The vehicles, including a tank and a helicopter, continue to run despite there being no replenishing fuel supply in the 16th century – a logical problem which was resolved in the remake.

• A film remake in 2005 was titled Sengoku Jieitai 1549.
• A four-episode TV miniseries called Sengoku Jieitai: Sekigahara no Tatakai was aired in 2006 by NTV, directed by Kōsei Saitō.

• Japanese: Sengoku Jieitai
• English: G.I. Samurai
• French: Les Guerriers de l'Apocalypse
• Spanish: Eclipse En El Tiempo
• Croatian: Vrijeme je stalo u 5 i 18
• German: Time Slip – Tag der Apokalypse
• Norwegian: Tidsstorm
• Russian: Провал во времени
• Cantonese: Zin3 Gwok3 Zi6 Wai6 Deoi6
• Polish: W Pułapce Czasu

In the UK, the film was bundled with Golgo 13: Assignment Kowloon and The Bullet Train in The Sonny Chiba Collection Vol. 2 Region 2 DVD set by Optimum Home Releasing.^[1]

• The film is indirectly referenced in the Japanese light novel series Gate as research material for JSDF countermeasures against the Special Region's Imperial forces, and fire rams and ambush trenches (both of which appear during the battle against Shingen's forces in the film) are made use of by Zorzal's forces during the later Imperial civil war.

• The Final Countdown (film)
• Axis of Time
• Zipang (anime)
• Red Shift (novel)
• The Guns of the South
• Heaven's Soldiers
• Rome, Sweet Rome
• Gate: Jieitai Kano Chi nite, Kaku Tatakaeri