The date and time of the Longines mechanical watch are not accurate. How to adjust the time of a Longines watch? This is due to the fact that quartz mechanical watches use the oscillation of the balance spring as the time reference, and the oscillation frequency of the balance spring in mechanical watches is as high as 5 Hz, which leads to the inaccuracy of the date and time. Adjustment method: When the LCD displays the time, press S1 twice in succession to make the LCD display seconds. At this point, you can press S2 to calibrate. When the seconds displayed on the LCD are between 01-29 seconds, you can calibrate for being too fast, i.e., pressing S2 will quickly rewind the time back to zero.