The bidding 1C - 4H - 6D - P; P - P is not an auction you see everyday! Everyone at this table made great choices to make this a very interesting hand.
When your partner opens 1NT, you know almost exactly what kind of hand he holds. It is one of only 3 possible shapes: 4333, 4432 or 5332 - the balanced hands. And it sits in a very narrow point range: 12-14 if you are playing Acol; or 15-17 if you are playing Standard American.