http://revach.net/article.php?id=3606

Section: Revach   Category: Lists
7 Reasons Why We Break A Matza At The Seder
At the Seder instead of the usually Lechem Mishneh we have three matzos.  Very early on the middle matza is broken in half and sent away from the table for later consumption during Tzafun.  Why do we break the matza at the table?  See Revach Lists for 7 interesting reasons brought in the Otzar Divrei HaMeforshim why we break the matza at the seder.