I visited in November 2022. Due to lack of time and a pesky cough I was only able to visit Site 1. Other reviewers have accurately described these curious sites. There is also a large cave at Site 1 where it is speculated the jars were baked, as the cave has chimney holes. It is also likely more recently locals hid in the cave during bombing runs. One curious fact I can add, as stated prior, the jars were likely made for food and alcohol storage and perhaps alcohol distillage. However bone fragments and ashes were carbon dated to as many as 500 to 1000 years later (approx 900 AD). So the jars were repurposed by another generation for burial long after their initial use. 
I stayed at Pukyo B&B near the airport. Very nice people and excellent food. They also provide tours.