Umeboshi Plums

Have you ever tried umeboshi?
They are really popular here in Japan. They are super sour pickled plums.
They are most often in rice balls, or served on top of rice with black sesame.
But, you can also find umeboshi flavoured candies (hard candies and dried candy).
There is ume vinegar and paste.
And also ume-shu (alcohol).
I love umeboshi, because I love all things sour.
I first tried umeboshi paste in Canada, because the plums were just WAY too expensive for my budget. Since coming here, I have been able to enjoy them quite frequently. They are quite salty though, so make sure you don't over do it. I have tried many from the supermarket, but they are often artificially dyed and sweetened. So, after a few treks to some natural foods store, I now purchase naturally aged for 5 years in wooden barrels umeboshi. Yum yum yum.
In many of the macrobiotic books I own, there are recipes for healing teas using umeboshi (boiled with shoyu, or kukicha tea for example). I haven't tried anything like that yet, but I am definitely curious.
Something else I love, are Japanese mortar and pestles:  

I make my own ground sesame in here, and you can grind many other things too.... like umeboshi!

Here I was grinding up a few plums to mix with tofu for a dressing. Super yummy! I have eaten this quite frequently on top of steamed veggies at Macrobiotic restaurants here. 
Brown rice + black sesame + umeboshi is a match made in heaven, I tell you!
Do you like sour foods?? Do you like umeboshi?