A bit like 団子, it's a sweet with lots of history, but more of a Buddhist connection: The あん wards of the evil spirits and thus “protects” the rice (offered to ancestors at equinoxes).
In autumn, you'd call them おはぎ (like the bush clover, often using 粒あん), in spring you'd call them ぼたもち (peony, and normally use こし餡)
In summer, you can call them 夜舟
In winter, 北窓
It's not truly もち dough, because it still has some texture; and often mixes glutinous and non-glutinous rice.
Can be coated in just あん, but also ごま・青のり・きな粉 (mixed with sugar)・ずんだ・walnuts… (But 青のり I found absolutely sickening, even if diluted in きな粉 🤢). For ごま and walnuts, grind them up in a すり鉢 with some soy sauce and sugar.
Recipe
140 gr 餅米
200 gr water
Sit overnight, then cook with a very good pinch of salt. Pound, but leave some texture.
25 gr of あん for wrapping around the もち, or 17 gr if its the other way around.
作り方
You can 絞り them with a 茶巾 (or plastic wrap) to make them somewhat oval shaped.
Traditionally, it's あん around the rice; but if you then roll them in something else, it's common to have the rice around the あん.