Man Slain with Umbrella in Dispute Over Manners Sun Jun 9, 9:06 AM ET TOKYO (Reuters) - A Japanese man was so enraged by an acquaintance's failure to address him with an honorific that he stabbed the man to death with an umbrella, police said on Saturday. It was the second killing with an umbrella in Japan in less than a month. Ryuji Sakamoto, 32, was arrested Saturday and confessed to killing Takayuki Niimi, also 32, during a Friday night quarrel in the city of Sakuragi, some 170 miles west of Tokyo, police said. "It appears that Sakamoto harbored resentment of Niimi for quite some time because Niimi did not use an honorific when speaking to him," a police spokesman said. Sakamoto punched Niimi in the face several times and then, when he fell over, stabbed him in the head with the umbrella, police said. Niimi was taken to hospital but died soon after and Sakamoto surrendered early Saturday. Both men were unemployed, police said. Honorific terms of address are used constantly in Japan, even among friends, most commonly by adding the suffix "san" to a person's name. Failure to do so is seen as extremely rude. In May, a middle-aged man in southwestern Japan was stabbed to death with an umbrella, apparently in an argument over who had the right of way on a narrow road.