The '1.5 Click' is a technique to chord faster when playing minesweeper.
 The Trick
A common situation for Flaggers is flagging a mine and chording beside it to clear more squares. The original method is to press and release a right click (flag), then press and release both buttons (chord).
The '1.5' Click trick is to press and hold down the right button to flag. Press the left button as you start moving to the adjacent number, then release both buttons on the number to chord. Instead of the original "down up down up", you only click "down down up". This reduces your clicks by 25% and saves a lot of time. The quicker you start pressing the left button, the more time you save. The technique was invented by Damien Moore (Canada) and posted in the Guestbook on 8 Aug 2001. It was quickly adopted by the community.