Can I learn Torah on Christmas day or Nittel Nacht?

Is it better to learn, or not learn Torah (playing chess) on XMS and Nittel Nacht (Yiddish: ניטל נאַכט‎)? There are two opinions (שיטות): It is a mitzvah or it is forbidden. It is a Mitzvah De’oraita It is a mitzvah de’oraita of learning Torah every day and night. After all, what’s more important — a …