This sweet letter set by San-X Japan is so adorable! It features the very lovable Rilakkuma ("Relax Bear, in Japanese!) and his friends. There are 4 different designs of writing paper (10 sheets each, 40 sheets altogether) and 4 different envelopes (5 of each, 20 altogether)!! What a lovely way to stay in touch with your loved ones - getting cute letters in the mail is arguably one of the best things in the entire world.
Writing paper measures 19cm x 14.5cm

Official San-X product. Made in Japan (2013)