Japan’s most famous stone buddhas. There are over 60 of them in multiple clusters carved directly on natural stone walls on a hillside. Since many of the stone buddhas are badly worn or damaged from the elements or humans, the impression is that they are very, very old. Indeed, they date from the 14th century. No one knows who or why they were carved here. Belatedly designated as National Treasures in 1995.
The centerpiece cluster, named the Furuzono Stone Buddhas (古園石仏), includes the largest Usuki stone buddha. When I visited (at around age 10), its head was still detached from the seated body (lower photos). For years, there was major debate over reattaching the head or not. They finally decided to reattach the head in the 1990s.
Most all photos of the Usuki Stone Buddhas you see today show the head reattached. So the lower photos are more rare now, showing the head still detached. By the looks of it now, they did a great job reattaching the head. Looks seamless, like it was never severed before. It’s a Vairocana celestial buddha (Chuson Dainichi Nyorai 中尊大日如来), in case you’re a buddha expert.
Usuki Stone Buddhas are in the boondocks. Quite out of the way, but worth it. When I visited years ago, there was just a simple roof built over the buddhas (upper photo). But now, I see that the stone buddhas have a much more substantial shelter. Better protected from the elements since they are National Treasures. 
Nearest station is JR Usuki Station, then a 20-min. bus ride to Usuki Sekibutsu stop. Admission charged: ¥550 for adults, ¥270 for jr. high and younger.
Official: https://sekibutsu.com/english