I meant to post this yesterday, but in Japan 7th January is the day we eat "Nanakusa-gayu" （七草粥） which literally means seven-herb rice porridge. Another Japanese customs/traditions from the part of (or the end of) NewYear Celebrations.
People tend to eat and drink A LOT during the new years in Japan, so to eat something light and healthy like Nanakusa-gayu on the 7th day of the new year is thought to give worn-out stomach a good rest. But actually it is believed to bring longevity and health if you eat it on this day. I do it mainly for the former reason though.
The New Year is really important in Japan and there are SO MANY customs and traditons regarding New Year, but there aren't so many that I follow. This one is nice and easy (and tasty!), the seven-herb is sold at the suparmarkets so I do this every year :) (Actually we are supposed to eat it in the morning of 7th Jan but I couldn't be bothered cooking when i woke up so I cheated by doing it in the evening for a quick and easy dinner.)
The seven herbs (edible wild herbs they are) are:
Japanese parsley (seri), Shepherd's purse (nazuna), Jersey Cudweed (gogyō), Common chickweed (hakobera), Henbit (hotokenoza), Turnip (suzuna), and Daikon (suzushiro).