Calendar: What day is it today?

A calendar is a daily publication used to record dates and other related information. Each page displays the information of one day, called a calendar, one month, called a monthly calendar, and one year, called an annual calendar. There are many forms, such as calendar, desk calendar, calendar card, etc. Now there are electronic calendars, and China began to have calendars about 4,000 years ago. According to a page of Oracle bone calendar in Oracle Bone Inscriptions, it is proved that the calendar of Yin Dynasty has reached a considerable level. This page of Oracle Bone Inscriptions is the oldest almanac of all mankind, and this page of Oracle Bone Inscriptions is also called the calendar.