The lower house of the Japanese parliament has passed bills to strengthen the country's military preparedness, in a move described as epoch-making by the Prime Minister, Junichiro Koizumi.
By Charles Scanlon
BBC Tokyo correspondent
The bills, which have now been sent to the upper house and are expected to become law next month, will give the government more powers to respond to an attack on the country.
But they are considered controversial in a country that renounced the right to wage war more than half a century ago.
Japan's pacifist constitution severely restricts the country's troops
The three bills to prepare Japan for a military emergency have been a top priority of the government as it faces an increasingly belligerent North Korea.
It worries that the armed forces are so constrained by regulations that they would not be able to mobilise effectively in the event of an attack.
Under current laws, tanks are required to wait at traffic lights and local government approval is needed for any manoeuvres.
The bills passed through the lower house of parliament with a large majority, after the government won support from the main opposition party. It could become law next month.
The bills will give new powers to the central government to deal with an armed attack or perceived military threat.
The armed forces will also be able to commandeer civilian property and move more freely.
The change is seen as a significant breakthrough for a country that has been paralysed with indecision about the role and capabilities of the military.
Liberal and left-wing opinion remains deeply suspicious of the armed forces - a legacy of World War II.
Critics say the bills are too vague and give too much discretion to the government.
The opposition democratic party insisted on human rights guarantees before signing up to the new legislation.