Sentence:  The filing of an original or amended declaration , otherwise due on <WSD>January</WSD> 15 , 1962 , is also waived , if you file your Form 1040 for 1961 and pay the full tax by January 31 , 1962 . 
Meaning of the word marked with <WSD> tags:  the first month of the year; begins 10 days after the winter solstice