What might these small, red, fruity things have been?

When my daughter and I were in Kyoto and Takayama this summer, meals at both ryokans included tiny bowls of what seemed to be little, red, slightly sweet, and very refreshing round fruits. After doing some research when I came home, I concluded we'd been served umeboshi -- but when I bought a jar, I discovered that was not it at all (very salty!). Are there sweet umeboshi? I know my description is not very clear, but I have been trying to figure out what we enjoyed last year. Thank you!