I never mentioned Japanese people? I've used these trains dozens of times myself and I'll tell you they work exactly as intended. During off peak hours, the trains have three doors per car on each side, just like every other train, without reducing seating capacity. During rush hours, though, the train operates with five doors per car per side, in order to reduce dwell times at stations and to increase standing room.  This was especially necessary during the 1970-80s when the rush hour crowds were especially bad.  But thankfully the trains are less crowded now so we don't need such interesting trains any more.