Don’t do this unless you check with a grown-up first! If they say it’s okay, then you can chalk the door. (No markers, please!) Chalking the door is a way to remind yourself and your visitors that you welcome Christ’s blessings into your home. (You might welcome wise people, too!)
You can chalk the inside or the outside of the door frame. The tradition is to write the new year around the letters C, M and B – or 20+C+M+B+21. The names of the wise men who visited the Christ Child were Caspar, Melchior and Balthazar. Some people think the letters might also stand for the Latin Christus Mansionem Benedicat, too – or Christ bless this dwelling.