Strumming the Guitar
Downstroke Only

Much like picking, strumming the guitar uses a cyclical motion. For now, let's assume that the picking-hand will always move up and down, even in periods of silence. The motion will ensure that strums are placed on the correct beats. Let's strum the following rhythm with an E minor chord. The downward (
) symbol will stand for a downstroke and the carrot (
) symbol will represent an upstroke.
Downstroke and upstroke

Strum the chord four times in succession, using down strokes. Even now, you are using a down-up, down-up strumming pattern. How do we know? Once you have completed one downstroke, your hand must come up again to make another downstroke. Let's hit the strings on the way up now.
Variations

If we use these 8 strums as a basis, we can remove some of them and create a large variety of sub patterns. When a beat is removed, continue the motion. For instance, in the next example, the third "down" strum is silent. Strum downwards, through the air, so that you can complete the following strum upwards.
Put it Into Practice
Try to see how many different strumming patterns you can come up with, using these 8 notes as a basis. How many combinations are there, theoretically? How many can you make?
