This method is for high volume production. The technique saves a great deal of time when doing dozens to hundreds at a time. The shell is easy to remove, and opens it up for deveining in one motion.
Always use proper knife skills to avoid injury.
Begin by laying the shrimp in front of you, tail toward you.
Grasp and twist the head to remove.
Save the head for stock.
Straighten out shrimp tail by pressing down with your middle finger and straightening with the thumb and ring finger. Lay the knife on the flat part of the tail and insert knife tip.
In a straight and forward motion, run the knife under the shell and slide up. With repetitive practice this step becomes quite fast.
Pull back shell with thumbs.
Identify the vein.
This image shows the vein, shell, head, and the tail - which is now ready for cooking.
Repeat with remaining shrimp.