Yojôhan fusuma no urabari: Shinobi hada (1974)

Shinobi Hada is the main girl here — slim, late 20s, short dark hair, small tits, totally comfortable being naked and sweaty on camera. She’s fucking a guy around her age, same ethnicity, also slim with short dark hair, both of them grinding hard on a bed in what looks like a low-budget hotel room. They start off with slow missionary, faces close, her legs wrapped tight around his back. Then they flip to doggy — he’s pulling her hips hard into him, one hand tangled in her hair, the sheets bunching up under their knees. There’s a second woman in the mix too, early on seen lying beside them, touching herself and occasionally joining in with some light fingering of Shinobi. Lighting’s dim, mostly from a single candle on the nightstand, so it’s moody but still clear enough to see the sweat on their backs and the way Shinobi’s eyes roll back when he slaps her ass. Final scene cuts abruptly to a random middle-aged guy standing alone by train tracks in daylight, which makes zero sense — maybe a deleted scene or wrong file merge, but it’s gone in seconds.