I've always considered that these were merely blemishes in the skin, usually in response to the fruit brushing against adjacent branches, etc. They always appear to be confined to the 'skin', and do not penetrate into the flesh of the fruit.

Mechanical forces most commonly from branches rubbing on the fruit can cause some minor cosmetic damage, but this is usually slightly raised and light brown in color. The dark flat spots you found on the fruit growing on the southern side of the tree is superficial sun damage, which again has only cosmetic importance.

Scott, my Hachiyas are still ripening on the tree and I'm still hoping for an Indian summer situation to allow for full ripening. I'll let you know if I see any of the dark interior discoloration in mine once I harvest them.

At this point it does seem to be cosmetic only. Thanks for the replies.

Scott F. Smith brought up a point. Some persimmons have blackened areas INSIDE the fruit, mostly (but not only) where the seeds are supposed to be. There was a black area and as I pressed on that area, it had the look of a rotted seed. But I don't know if that is what it was. I am speaking of a Hachiya persimmon, as the other type I have never seen those blackened areas inside the fruit. One or two areas were actually Obvious seeds, but one or two areas there was no way to tell. Anyone?

Maybe just a little sunburn.

Some American persimmons have black specks in the flesh... which someone (Jerry Lehman, I think) told me, years ago, were flecks of condensed tannins. Unsightly, but not contributing to astringency or off-flavors... but a trait to be selected against in a breeding program.

Ernesto Moreno - 2 years later here. LOL. I frequently found the same things (blackened charcoal like substance - they are not solid mass as upon touching they disintegrate- , always found right next to actual seeds or in that center seed areas) in well ripened Hachiya every year. I would usually just take the "stuff" and consumed the fruit without any issue. But this year, I decided to take time to find out what they are and came across this forum. I always thought they are unmaterialized seeds because of their locations and shapes. I would like to know if anyone has scientific factual information.