The National Police Agency notified prefectural police forces nationwide Friday of new guidelines regarding the use of firearms, clarifying the circumstances in which officers may be allowed to fire their revolvers.

A rise in serious crimes, as well as a series of incidents this year in which police officers have been killed in the line of duty, have prompted the NPA to issue guidelines that better define the circumstances in which a firearm may be used, agency officials said.

Many observers say the move effectively relaxes the rules regarding the use of weapons by officers in self-defense.

Specifically, the revamped guidelines, which take effect Dec. 1, do not change the condition that "there should be no other means" available when an officer discharges a firearm, as stipulated under the Law Concerning Execution of Duties of Police Officials.

However, it lists roughly 80 specific instances in which an officer would be allowed to shoot, including, "no warning shot is needed when a person rushes at you with a knife or sword."

According to the NPA, Japanese police have placed priority on using batons rather than guns when subduing crime suspects. The current guidelines only offer abstract phrases such as "(an officer) may shoot to the minimum possible extent," which has meant that officers have refrained from using their pistols even in dangerous situations.

The new guidelines distinguish between the use of batons and firearms and provide specific rules for when an officer may unholster a firearm, hold it at the ready, fire a warning shot or shoot at an attacker.

For example, an officer may unholster a gun when approaching "the scene of a crime where someone is in possession of a lethal weapon." A police officer may hold it at the ready when "a person with a knife tries to attack a passerby."

Shots may be fired without warning in the event "a gang of people rush toward you bearing dangerous weapons" or when "a person charges with a knife or similar object when approached by a police officer for questioning."

Official statistics show that cases of serious crimes, such as murder, have risen by about 60 percent over the past decade. In addition, the number of police officers injured or killed in action have increased from 26 in 1996 to 54 in 2000.

With these statistics in mind, NPA officials supported the clarified guidelines for weapons, saying they believe it is unrealistic to believe that law and order can be preserved when police officers are wounded or killed before a suspect can be apprehended.

One symbolic case was the death in August of a Tokyo assistant inspector who was fatally stabbed by a man on a shopping street in Setagaya Ward. The officer fired four warning shots into the air, but only fired at his attacker when he was pushed onto his back with his assailant sitting on him and stabbing him. Both men died.

The incident led the NPA to report to the National Public Safety Commission that it believed it needed to rewrite the guidelines if officers were under the impression that warning shots should always be fired.