I need the name of something I ate in a Japanese bento?

I had a saba bento last night with broiled mackeral, potatoe salad, rice, takuwan, some kind of chicken and stewed vegetables. Inside the stewed veggies compartment was stewed chunks of daikon, carrot and taro. There was also a ball of something resembling a fish ball. I thought that'd what it was until I bit into it. It was really soft, and tasted something like yam/taro/potato all mushed up and formed into a small ball the size of fish balls. It wasn't very salty, sweet, sour, bitter or flavourful. I'd like to know what this particular item is called. By the way it was a light beigey-grey color, it looked just like a fish ball.I need the name of something I ate in a Japanese bento?
It is called araimo.

Araimo is small starchy japanese potato . It is usually shaped in a small ball form and then cooked with the veggies. Its pretty much tasteless but very starchy and served with veggie side dishes known as oden.I need the name of something I ate in a Japanese bento?
I think what you are talking is called Ume that is the only thing I know of that looks like a fish ball.I need the name of something I ate in a Japanese bento?
perhaps umeboshi (pickled plum), but those are usually salty/sour.



picture:

http://www.spiced.com/SPICED/SKU/jade/J_鈥?/a>I need the name of something I ate in a Japanese bento?
No, it is not ume, but I think it has some sort of white beans or something like that... I'm sorry I never learned the name either but I just wanted to say it is not ume like the guys say