[Cultural Seed of Knowledge - Custom of giving a parting gift (senbestsu)]

A “senbetsu” is a parting gift given to an acquaintance, colleague, etc. who will move residence, be transferred at work, change jobs, advance to higher education, go on long holiday etc.
This gift is given as a gesture of gratitude and good fortune.
The gift should be chosen by taking into account one’s relationship with the person up to the present, the persons, status, and the person’s lifestyle hereafter.
If a gift is received when one moves residence, a return gift is not required.
However, letter of gratitude must be sent.
If a gift is received when going on long holiday, a souvenir should be bought for the giver.

[Nara Lifestyle Guide / Sending Parcels (Domestic)]
http://www.nifs.or.jp/mobile/eng/guide/lifestyle/lifestyle08.html

[Seasonal Life Tips / Low-cost heating appliances, etc: Kotatsu / disposable packet warmers]

A “kotatsu” is a low table with electrical heating below it and is covered with a “futon” (quilt).
You sit with your legs under the table to get warm.
Its good points are it is electricity efficient and low-cost, and does not dirty the air in the room.
It can be used as a table for meals, a living room table, or a study desk, etc.
“Kairo” or disposable packet warmers utilize the combustion qualities of iron powder.
They can be attached to underwear, socks, or put in one’s pockets.
The heat from “kairo” lasts more than 10 hours.
They are easy to use, safe and cheap.