Stamps issued by Macao portray the love story between Niu Lang and Zhi Nv. [Photo/youlai18.com]

Day August 9 this year marks Chinese Valentine Day, the seventh day of the seventh lunar month.

The festival came into form based on a fairy tale in China: the romance between Niu Lang, represented by the star Altair, and Zhi Nv, represented by the star Vega.

In the story, the couple lives on opposite sides of the Milky Way and the only time they can be together – on a bridge formed by flying magpies - is on the seventh day of the seventh lunar month.

The fairy tale is commemorated on stamps issued by post offices in many provinces around China. Here are some examples.

Stamps issued in 2008 by Zibo in Shandong province tell the story of Niu Lang and Zhi Nv. [Photo/youlai18.com]

Bold primary colors punctuate the scenes between legendary lovers Niu Lang and Zhi Nv in this set of stamps issued in 2010 by China Post. [Photo/youlai18.com]

This 2015 stamp was issued by Zibo in Shandong province for Chinese Valentine Day. [Photo/youlai18.com]