Well, if viki doesn't get it, it's available somewhere. I easily found it. Of course I'm not allowed to post a link, but a very short search should yield results.
For other people.
Here is the summary I found:
15-year-old Ikeuchi Aya is an ordinary girl, the daughter of a family who works at a tofu shop, and a soon-to-be high schooler. However, odd things have been happening to Aya lately. She has been falling down often and walks strange. Her mother, Shioka, takes Aya to see the doctor, and he informs Shioka that Aya has spinocerebellar degeneration - a terrible disease where the cerebellum of the brain gradually deteriorates to the point where the victim cannot walk, speak, write, or eat.
User reviews from that site:
_I watched a lot of K-drama and J-drama that a lot of people say that would make you cry but I never cried that much while watching it, It makes me sad but not to the point that would make me cry that much teary eyed maybe?? But this drama broke the record! 1 Liter of Tears indeed! I've watched it twice already but the impact of the drama in me is still the same! I'ts the only time that I watched a drama that would make me cry and sad soooooo much!!
Such an amazing story!!
Little drops of water is what makes an almighty ocean!
You are really gonna need 1 litre of tears till you reach the final episode (TT)_
Too much tears.. this show really'll break you heart...
I watched this over 10 years ago and still to this day, this is the saddest thing I've ever watched. You just cannot compare this to anything else. It still withstands as being iconic to me...there's just so much meaning to it. I'm not entirely sure if I'd watch it again though - just cos I'd cry all over again and be in such a state. (Just to give you an idea: I remember I cried every episode except the first. And by cried, I mean sobbed.) However, you cannot miss this. Just prepare yourselves!
So, yeah, I think I'm going to skip. Enough sad things happening around me...