Japanese beaches that aren't ultra popular tourist destinations are currently flooded with trash. Going through Shizuoka, Aichi, and islands of Kagoshima, they're increasingly looking like dumps. Some are completely covered in pieces of trash, and most of it isn't Chinese. It's washed up laundry detergent bottles and toys and stuff all from here. Some places like Okinawa and Kamakura beach are generally cleaned, but having visited Kamakura 4 years ago and again a year ago, it's noticeably filthier.
Major beaches are maintained and cleaned daily. Walk a few hundred meters beyond the crowds and there's a good chance you'll see trash everywhere. Two weeks ago I visited a beach I last went to a couple years back, and it was depressing seeing the state of it. The beach used to have crabs and isopods roaming the sands and crawling around the rocks. Now it's covered in shards of plastic and washed up tires and other things. Not a crab to be seen.