One Click Bug

The One Click Bug occurs when the minesweeper timer does not stop after a game is solved in one click. This is a Bug on the Beginner level of Windows Minesweeper.

History

It has long been known that minesweeper always makes the first click safe. If your first click is above a mine, the mine is moved to the top left corner. If this corner already contains a mine, the next available square to the right is used. It is not clear who first discovered this phenomenon, but it was a common observation when this author joined the community in 2000. In 2003, Usman Latif debugged Winmine and published the code for this StepSquare function on his website.

Case Cantrell (USA) suggested in the Guestbook on 25 Jan 2003, "Could be that there is not supposed to be a 1 sec game, and if you hit a mine on the first click and it moves to the top left and creates a 1 sec board then it causes the bug." This turns out to be true, but it was discovered earlier. The 8x8 Beginner level of Winmine contains two Board Cycles with a total of 48624 unique boards. Tim Kostka analysed these boards in 2002 and discovered that none of them could naturally be solved in one click. Instead, there were five boards that transformed into a 3BV of 1 if your first click moved a particular mine. Only four of these boards can be solved in one click, because the fifth turns your first click into a number. Your chance of winning in one click is roughly 1 in 800000.

This is where the Bug occurs. Winmine does not expect the starting click to also be the last click. As a result, the timer does not stop. The player is forced to click on a mine to stop the clock.

Pictures

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  First reported example as played by Damien Moore 26 Mar 2001. Clock stopped at 1s because his 2nd random click hit a mine.

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  Another example as played by Matt McGinley in August 2001.

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  An example found by Tim Kostka for his article in 2002.

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  First known case of the Bug on Windows XP, as played by Benjamin Green on 29 Oct 2006.

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  Another XP example as played by Linus Wang on 31 Oct 2007.

Videos

• One Click Bug Videos - Two videos of the bug. The first video is of one of the boards above, the other video is the fourth board Tim found.

Comments

Analysis by Rodrigo Camargo revealed that there are no Board Cycles on the 9x9 Beginner level packaged with Windows XP and later. These games have thus not been catalogued and researched. On 14 Mar 2004 Dennis Lütken reported in the Guestbook that he had played a 3BV=1 Beginner game on XP that did not have a mine in the top left corner and the clock had stopped. This suggests some one click games may occur naturally. However, on 29 Oct 2006, Benjamin Green played a 1 click XP Beginner game and the clock did not stop. This suggests the Bug is present. It is not yet known if the Bug occurs on the version from included in Widows Vista and later. None of the official clones used for the world ranking have ever experienced this Bug.

Links

• 1 Sec Theory - by Matt McGinley (13 May 2002)
• TLM Theory and the One Click Bug - by Tim Kostka (Dec 2002)
• Minesweeper First Click Behavior- by Usman Latif (30 Nov 2003)
• The Board Cycle Bug of Microsoft Minesweeper - by Rodrigo Camargo (23 Sep 2006)