The Modern Dovetail Shuffle
In the old original version of the dovetail shuffle, several selected cards were pushed into the pack diagonally, then straightened at the back of the pack so that their ends protruded an inch or so. The student was instructed to seize these protruding ends, pull the cards out of the deck, and then place them on the top or bottom as might be required for the trick. A difficult operation to do imperceptibly, unless the spectators obligingly looked the other way.
The modern version is not only easier, but, during its performance there is nothing to cover up, a rare delight in sleights. The cards are simply pushed into the pack, well separated, and you proceed to shuffle, the cards are all together and under control immediately.
Let us suppose that you are using four cards, which have been removed from the pack. You can fan the deck in your left hand with the faces outward, and press firmly on the back of the fan with your left thumb. Take up the four cards, one by one, and insert them in the pack at the top edge of the fan, allowing at least three quarters of each card to protrude. The firm grip maintained by your left thumb will hold the cards securely in position. (Fig. 9).
You show the cards thus, then close the fan with your right hand on to your left, gripping the pack at the middle of its sides between the tip of the thumb on one side and the tips of the second and third fingers on the other. The four protruding cards now lie one on the other. You bring your right hand, the fingers spread and extended so that the side of your third finger strikes against their outer sides. The tip of the second finger fails on the top of the four cards and your third finger is on the far side Of them.
With these three fingers push the four cards a little to the left, then by pressing downward with the second finger tip push them diagonally through the pack until you feel the inner left corners strike the ball of your right thumb at the bottom of the pack. Now move the tip of your right second finger on to the opposite corners which protrude a little from the top of the deck. (Fig. 9).
Without removing the right hand you turn the pack upward to the position for the overhand shuffle; the ball of your right thumb still presses on the lower projecting corners of the four cards, and the tip of the right second finger secures the diagonally opposite corners of the same cards which protrude at the top of the pack. The four cards are thus held firmly between the right thumb and second finger and you could lift them out by one motion, but this must be done under cover of an overhand shuffle.
In lifting the pack with your right hand for the first movement in the shuffle you must press it between the right third finger on the face of the deck and the first finger on the back, otherwise all the cards but the gripped four will fall into the left hand at once. By relaxing the pressure of the first and third fingers you allow packets of cards to fall into your left hand as they are pulled off by the left thumb, exactly as in the regular shuffle. The four diagonally placed cards will be found to cling to the fingers to the last, and the final movement of the shuffle is to drop them all together on the top of the pack.
Every action in this highly effective sleight is either a natural one or is completely under cover. Some little practice is necessary to hold the pack securely and shuffle freely, but that small trouble will be repaid a hundredfold by the mastery of one of the most useful sleights in the whole range of card magic. The fanning of the pack and the insertion of the four cards lend themselves to graceful motions, the effect is convincing to the audience, and the action is quick and snappy. What more could be required?