Its called o-toso, I was a little child but I do not remember exactly when I first had it.
In Japan, it is just a traditional thing to have o-toso, a cup or sip of sake on New Year Day.
I did not know what it meant or anything, but I was looking forward to it every year even though I did not like the taste of it.
Well, I still do not know what o-toso is, but luckily we can look it up in Wikipedia. Hehehe.
Here it goes.
Toso is drunk to flush away the previous year's maladies and to aspire to lead a long life. For generations it has been said that "if one person drinks this his family will not fall ill; if the whole family does no-one in the village will fall ill", and has been a staple part of New Year's osechi cuisine in Japan.
Now we probably had good enough amount for a whole world this year to avoid swine flue!