A gap is defined as an unfilled space or interval. On a technical analysis chart, a gap represents an area where no trading takes place. On the Japanese candlestick chart, a window is interpreted as a gap.
In an upward trend, a gap is produced when the highest price of one day is lower than the lowest price of the following day. Thus, in a downward trend, a gap occurs when the lowest price of any one day is higher than the highest price of the next day.There are 4 types of gap , which depends on the area the gap is formed.