Christmas is not an observed holiday in Japan, of course, because only 0.7% of the population is Christian (according to the CIA World Factbook).
Instead, New Year’s is the big holiday, and is the time when people do many of the things that we associate with Christmas: they exchange greeting cards, travel to spend time with families, have special dinners, go to the shrine at midnight in order to pray, and give gifts to children (usually money).
Also interesting to note is that when there has been a death in the family, no immediate relatives send out New Year’s cards that year. But they do send out similar greetings in early November or December to let their friends know not to expect any New Year’s cards!