If Japan revises the Constitution's war-renouncing Article 9 and officially designates its military as such, other parts of Asia will increase their arms buildups and war will become a possibility, according to American film director John Junkerman.

The Tokyo-based director, who recently completed the documentary "Japan's Peace Constitution," said in an interview that Article 9 has kept Japan from resorting to use of force and reassured other parts of Asia that the country does not pose an aggressive threat.

"But if Article 9 is revised and the Self-Defense Forces are called (a) military and given that right of being engaged in collective . . . defense, Japan's neighbors are going to say 'there is nothing anymore that constrains Japan, so therefore we have to rebuild up our arms as well,' " Junkerman said.