About $72 million worth of cocaine stuffed into backpacks has washed up on beaches south of Tokyo in Japan's biggest-ever seizure, reports said Friday.Two more bags were found Thursday after an elderly local resident discovered four drug-filled rucksacks, outfitted with a buoy and illuminated markers, earlier this week.In all, there were 120 kilogrammes (265 pounds) of plastic-wrapped blocks of cocaine inside the bags, which police suspect were lost by seafaring traffickers, the leading Yomiuri Shimbun and other media said.A police spokesman declined to comment on the reports.Japanese police seized just 6.6 kilogrammes of cocaine last year, down from 28.7 kilogrammes in 2011, according to the National Police Agency.