Few end-of-the-year customs in Japan seem sillier to the casual observer than that of the mochū hagaki  (喪中葉書, "mourning postcard"). Mochū hagaki  (pictured above) are postcards sent out to friends, relatives, co-workers, and others in December or earlier, notifying them that due to the death of family member in the past year they are in mourning and will therefore be unable to send nengajō (年賀状), or New Year's greeting cards. It is as if people are saying, "FYI: I am sending this postcard to you now to inform you that I cannot send you that other postcard later."

To be fair, mochū hagaki do serve some useful purposes. For one, they inform others that they need not bother sending a nengajō to the family out of respect for their loss—even when the person who has died was 105 years old, as is the case in the postcard on the left, and "relief" rather than “sorrow” might be a better adjective describing the emotions felt when Great Grandpa finally kicked the bucket. And, probably more importantly, mochū hagaki preemptively assuage any misunderstandings that might occur when a nengajō goes unanswered.