The K line, also commonly known as a candle line or yin and yang line is upright crude sticks that are used to represent the daily opening and closing price of a stock. Each K line represents a specific time period. When the highest price exceeds the opening or closing price, it is presented by a straight line on top of the thick candle. This is often known as the upper shadow. Similarly, the lower shadow also exists to represent the lowest price as well.