Introduction: The Red Vs. Blue Card Trick

Introduction
Looking for an amazing magic trick that's easy to perform and easy on the wallet? Look no further than the Red vs. Blue Card Trick! Amaze audiences as you change the back of a chosen card from red to blue! Shock them when you do it a second time but with an ending they'll never see coming! 

What You Need
1) Two decks of cards. Ideally, both decks should have similar designs on the faces and backs. The only difference between the two decks should be the color of the backside (or some other small difference like a mark or sticker on the backside). For the purposes of this tutorial, we have selected one red deck and one blue deck. One deck will serve as our primary deck (red), while the other will serve as our secondary deck (blue). Before beginning the trick, you will need to select your Trick Card and your Dummy Card. Again, for the purposes of this tutorial, we have selected the 7 of Clubs and the 3 of Diamonds. The 7 of Clubs will serve as our Trick Card, and the 3 of Diamonds will serve as our Dummy Card.

Set-Up
Follow the steps listed below before performing for an audience:

1) Open both decks. Remove the promotional cards and jokers from the red deck. From the blue deck, remove the blue trick card (blue 7 of Clubs) and set it aside. From the red deck, remove the red trick card (red 7 of Clubs) and red dummy card (red 3 of Diamonds).

2) Take the red deck. Place the red 7 of Clubs on the bottom of the red deck. Now place the blue 7 of Clubs on the bottom of the red deck. Now place the red 3 of Diamonds on the bottom of the red deck. Your three bottom cards should be the 3 of Diamonds, the blue 7 of Clubs, and the red 7 of Clubs from the bottom-up.

Performing the Trick
From this point forward, you will be using the Red Deck you constructed during Set-Up when performing. You will no longer need any other cards from your Blue Deck, and it is recommended that you store it somewhere away from your audience to keep them from catching on to your trick.

Step 1: "May I Have an Assistant From the Audience?"

Ask for an assistant from your audience. Tell your assistant that you are going to shuffle through the deck and that you want him (or her) to say "Stop" at any time as you shuffle. Step (2) will teach you how to shuffle the deck properly for this trick.

Step 2: The Hindu Shuffle: "Tell Me When to Stop..."

Hold the red deck in your right hand so that the backs are face-up and your palm is above the deck. Hold the deck with your fingers to keep a loose grip. It's best to hold on to the deck's two long edges.  

While gripping with your right hand, grab the red deck with your LEFT hand so that the palm is below the deck and your middle finger and thumb of your left hand are on the two long ends of the deck. 

With the middle finger and thumb on your left hand, slide a few cards off the top of the red deck into the palm of your left hand. Be sure to keep your left hand below your right hand. Continue to slide cards off the top of the red deck until your assistant says “Stop.” (If you can slide cards off the top fast enough, it will appear as though you are shuffling through the deck. This shuffling technique is known as the Hindu Shuffle.)

Note:
Remember not to shuffle too fast, or you will run out of cards! Also, if your assistant doesn’t say “Stop” before you reach the bottom of the deck, don’t panic! Place the cards in your left hand on top of the cards in your right hand. Ask the assistant to stop you sooner, and repeat Step (2). Be sure to keep your blue card hidden during the process.

Step 3: "You Stopped on the Three of Diamonds!"

When your assistant says “Stop”, show him the bottom of the deck in your right hand. It should be the 3 of Diamonds. All you have to do is show the card face. Do NOT take the card out of the deck.

Step 4: "I Will Now Place the Three of Diamonds Back Into the Deck!"

Place the cards in your right hand on top of the cards in your left hand.

Straighten-out the deck.

Spread the cards out on a flat surface with all the backs facing up.

Step 5: "One of the Cards Is Now Blue!"

Find and point-out the one card with a blue back to your assistant. This is the blue 7 of Clubs. Do NOT turn it over or remove it from the deck.

Remove all the cards that are on top of the blue card and set them off to your right. Be sure to keep them in a neat pile, because you will use them again in Step (7).

Straighten-up the remaining cards with the blue card on top. Now hold the deck in your right hand.

Step 6: "I Turned the Three of Diamonds Blue!"

The top two cards should be the blue 7 of Clubs and the red 3 of Diamonds, but do NOT show the audience this. The first picture is for clarification. Carefully pick up the top two cards of the deck with your left hand so that it looks like you are only picking up a single card. This will take some practice.

Pretending you picked up only one card, show your assistant the face of the 3 of Diamonds. It should appear as though the back of the 3 of Diamonds has turned blue.

Step 7: "I'll Perform the Trick for You Again..."

Return the 7 of Clubs and 3 of Diamonds back to the top of the deck in your right hand.

Slide the blue-backed card (the 7 of Clubs) off the top of the deck. Be sure to keep the back-side up and the card face hidden from view from your assistant and audience.

Place the 7 of Clubs face-down on a flat surface, but still in plain sight. Tell your assistant that you are going to perform the trick again, but are removing the “3 of Diamonds” from the deck.

The 3 of Diamonds should still be on top of the deck in your right hand.

Place the deck in your right hand on top of the deck you set off to your right in Step (5).

Straighten-up the deck.

Step 8: "You Stopped on the Seven of Clubs!"

Shuffle the deck as you did in Step (2). Ask your assistant to stop you again. This time, when your assistant says “Stop,” the card you show them should be the red 7 of Clubs. Remember that it's on the bottom of the deck in your right hand.

Place the cards in your right hand on top of the cards in your left hand. Straighten-up the deck.

Step 9: "The Seven of Clubs Is Now Blue!"

Spread the deck of cards on a flat surface so you can see the backs of the cards. Pretend to look for a card with a blue back. Tell your assistant you can’t find any blue cards. Then say you notice that there is one blue-backed card on the table. Indicate the blue 7 of Clubs you set aside in Step (7). Flip the blue card over to reveal that it is a 7 of Clubs!

Final Notes
Remember that it is not essential that you use specifically the decks and cards from this tutorial. The only requirements are that the two decks be nearly identical with the exception of one or two small differences in the back design that are easily recognizable (color is generally the simplest way to generate this effect), and that the values for the Trick Card and Dummy Card are selected in advance and prepared correctly.