Akira Maeda chest\stomach injury?

[El Fiasco]

I was watching Akira Maeda's big grudge match with Super Strong Machine(Junji Hirata) from 8/20/87, and I noticed Maeda had a scar on his chest, just above his stomach but below his breast. It wasn't very long, but it was obviously deep and had required stitches. It didn't look like an in-ring injury, I've never seen a guy get cut on his chest like that(unless it was a possible boot to the mid section gone awry?).

Anyway, I was wondering if anyone(Hisa, maybe?) could tell me what this wound is from, because it almost looked like he had some minor surgery done there.

[Tradewynd]

I've seen matches of his after that, and never noticed that scar. The VQ on the tapes isn't the best, but that one sounds pretty hard to miss.