The Diet enacted legal amendments Friday to ban the possession of double-edged knives and tighten gun-ownership rules in response to a series of violent crimes involving the weapons.

The move marks the first revision in 46 years to the 1958 Firearm and Sword Control Law and the first change in 28 years to the rules governing gun ownership.

A bill to revise the law cleared the House of Councilors Friday morning after passage by the House of Representatives.

The new rules on knives will come into force a month after promulgation of the revised law. Those on guns will take effect in a year.

The revised law will ban the possession of daggers and other double-edged knives with blades 5.5 cm or longer.

Ownership of swords, knives and spears with blades 15 cm or longer is already prohibited.

The revision expands the ban on gun ownership to include people with police records pertaining to stalking and domestic violence, as well as people who are bankrupt or thought to be suicidal.

Based on a bipartisan revision, people applying for gun permits must submit medical certificates from psychiatrists.

The revisions, worked out by the National Police Agency, were prompted by a series of crimes, including a shotgun rampage last December in Sasebo, Nagasaki Prefecture, that killed two people and injured six others, and a vehicular homicide and stabbing spree in Tokyo in June that that left seven people dead and 10 others wounded in the Akihabara district of Tokyo.

In the Akihabara rampage, the suspect stabbed people using a 13-cm dagger that was legally purchased.

The Nagasaki gunman had a firearm license.

There will be a six-month grace period after the new rules on double-edged knives come into effect. During that period, owners of the knives will have to surrender them to police or ship them overseas.