There are no rules as to how many doji might appear in a row. You might find four or five straight doji at a time. When this happens, you should look at the shadows as they are produced. These might suggest that a stock is going in some direction. A layout with lots of doji in a row will suggest that the value of the stock will not change much. That is, any reversals that occur will be minor. In fact, you might even find a continuation in the stock if you see lots of doji laid out in this manner. Review the total volume of the stock when those doji show up. The odds are no one is actually trading the stock at the time, thus making it hard for the stock to move up in value.