You may wish to review Introduction To Strumming before continuing with this lesson.

There are many different combinations and I have come up with a simple system to generate random strumming patterns which include both upbeats and downbeats:

Begin by doubling the upper number of the time signature (which tells you how many beats per measure).  This will give you an equal number of downbeats and upbeats.  Create a graph which contains that number of columns.  We will used 4/4 time for this example so our graph will contain 8 columns.  Label the downbeats and upbeats in the first row (downbeats on the numbers and upbeats on the "ands").  Check the box under the first downbeat, as you will always want to strum on the first beat.  Now randomly check some of the other boxes.  In each of the examples below, I have checked  four other boxes in addition to the first downbeat.

1                        +                        2                        +                        3                        +                        4                        +
X                       X                                                  X                       X                                                  X


The X's indicate when to make contact with the strings.  It is important to note that the hand will pass by the strings whether or not it makes contact.  For example, in the first strumming pattern, the right hand makes contact on the first downbeat and the first upbeat.  On the second downbeat it passes by the strings without making contact (as it does on the third and fourth upbeats).  It is important to keep the right hand passing over the strings even when it does not make contact.  This creates an even and predictable movement of the right hand which, in turn, gives the player significantly more control over the rhythm.

Here is another example in 3/4 time:

1                            +                            2                            +                            3                            +
X                           X                           X                                                          X                            X

In this case there is only one instance when the right hand is passing over the strings without making contact.  Still, this is considerably more interesting than strumming on every downbeat and upbeat.