Newly declassified documents reveal behind-the-scenes discussions over the first overseas operation for Japan's Self-Defense Forces. Thirty years ago the team helped clear mines from the Persian Gulf.

The United States had failed to persuade Japan to join its coalition following Iraq's invasion of Kuwait.

Japan's Prime Minister Kaifu Toshiki at the time said, "Our pacifist constitution does not allow us to take part in the military coalition. We need to offer due financial support."

Tokyo provided 13 billion dollars, a move some outside Japan described as "too little, too late."

Debate within the government over the role of the Self-Defense Forces continued.

The Vice Foreign Minister pushed to send an SDF unit on a mine-clearing mission, saying Japan should help secure the waters it relies on to import oil.

But one senior official wondered if that contradicts the law, saying international cooperation cannot be the sole reason for sending the SDF overseas.

Two weeks later, bureaucrats found a different rationale. The mission's purpose would be ensuring the safety of Japanese ships after the ceasefire. A team was dispatched and disposed of 34 mines.

Japan would soon enact a law enabling the SDF to take part in peacekeeping operations. That allowed it to expand its work, including joining the UN mission in South Sudan and combating piracy off the Somalian coast.