Postcards in summer (暑中見舞い and 残暑見舞い)

We don't recently write a letter or postcard to friends. We can contact them easily now. Almost people use e-mail of cell phone or computer. Even elder people can use e-mail and contact with grandsons or granddaughters with photos. Handwriting is rare thing in daily life or business. It is so convenience, however, e-mail is sometimes literal and it is difficult to feel emotions of the sender. There is a custom to write postcard in summer in Japan.
"Shochu Omimai Moshi Agemasu" and "Zansho Omimai Moshi Agemasu" are first phrases to write in postcards. Japanese write postcards to ask friends how he or she has been getting along in summer. "Shochu" 暑中 means the hot period from the end of rainy season to Liqiu (August 7 in this year). and "Zansho" 残暑 means the heat after Liqiu. So we write "Shochu Mimai" before Liqiu and "Zansho Mimai" (We call each postcards as "Shochu Mimai " and "Zansho Mimai".)
I have received a Shoshu Mimai from my friend this year. I was very glad. Receiving a letter or postcard is glad and special for us. (Do you think so ?) As I mentioned before, we seldom write a letter now. However, I think that this is good custom.

This is image of Shoshu Mimai