I received your letter, in which you said that you used to chant one chapter of the Lotus Sūtra each day, taking twenty-eight days to finish chanting it once; and that recently, however, you chant only the “Previous Life of the Medicine-King Bodhisattva” chapter each day. Then you asked: “Should I chant each chapter each day as I used to?”
You may chant the whole twenty-eight chapters, one chapter, one paragraph, one sentence or even one character of the Lotus Sūtra a day. Or, you may chant the daimoku, “Namu Myōhō Renge Kyō,” just once in a day or once in your whole life. Even if you may never chant the daimoku yourself, you may rejoice at hearing others chant it just once in your whole life. Or you may rejoice with others who rejoice at hearing a voice chanting the daimoku.
Gassui Gasho, A Letter on Menstruation, Nyonin Gosho