Whenever the supplier has a ten-valued card or an ace showing there is a risk of a supplier blackjack. In the early days all dealers used to peek beneath both tens and aces. Today, you'll solely occasionally see dealers peek and once they do it will normally be under aces solely. In many casinos dealers don't peek at all and easily wait until all players have completed their arms earlier than revealing his hole-card. In many casinos at present, tables are geared up with particular digital sensing units and particular cards are used to detect an ace in the gap. If the dealer manually peeks beneath tens there is always the potential of the vendor giving off a tell and there are methods to take advantage of this vendor weakness.