Police are fighting back against Tokyo's chikan - the men who get their thrills by groping women in Tokyo's crowded subway trains. Special squads of female police officers are patrolling trains and stations, particularly in the early morning when chikan strike most often. Chikan earned greater notoriety with the 1994 publication of a book by a self-confessed sex pest, Samu Yamamoto. A Groper's Diary, with its graphic accounts of his exploits, was a bestseller. Yamamoto claimed that he had groped an average of 12 women a day for more than 26 years. Many Japanese males apparently regard the crime as minor. 'It's a poor reflection on Japanese society,' said Mari Kaneko, a 20-year-old university student. One major obstacle to fighting the crime is the reluctance of women to speak up, especially the young ones who are most frequently targeted by chikan. Japanese police are attempting to break the silence through media and poster campaigns as well as by establishing taskforces at major stations staffed by female officers. The police launched a crackdown against chikan last month, during which 76 victims asked for help, and 36 arrests were made.