When he reviewed it later, this was the game that prompted Steven Medcalf to originally invent the Medcalf Defense. This was probably the best game I had ever played up to this time on Little Golem, but I still lost the game to Klaus (a very frequent occurrence!). Steven (on LG) later pointed out that I might well have won this game if I had been able to see how to apply a clever technique, which later became known as the Medcalf Defense.
I employed the Medcalf Defense in the championship game against David Bush during the 2006 World Boardgaming Convention championship game, its first known use in a live tournament, but still lost to David. ;-) You can see it employed here, in the corner of the board toward the upper left in the photo: http://www.mindspring.com/~alanh/twixt/wbc2006/wbc2006_twixt_final.jpg (I am on the left and playing Black; David Bush, playing red, is on the right; the photo is by Alan Hensel.)
Alan Hensel, who was observing the game at the time, thought I had made a serious mistake until he saw how it played out just a few moves later. David Bush quickly realized the potential of the technique, and was worried at first, but then recognized that he could use the red peg in the lower left of the photo as the resource he would need to still win the game.
Alan has prepared an excellent write up about the use of the Medcalf defense at: http://twixt.wetpaint.com/page/The+Medcalf+Defense
The first known use of this technique on LG was in game 469944: http://www.littlegolem.net/jsp/game/game.jsp?gid=469944&nmove=23 , not long after its invention.
Steven Medcalf himself employed it on LG almost at the same time in game 477915: http://www.littlegolem.net/jsp/game/game.jsp?gid=477915&nmove=14
The next two comments analyze the not just one, but TWO (!) different opportunities to have employed the Medcalf Defense within this game. _____________________________________________________________________________
After 5.s8 the Medcalf Defense could have been employed with 6.s67.q78.q59.o610.n611.m512.r1113.o1014.p1015.m916.l717.j818.k819.k620.k9 for a possible win early in the game. Of course it is also always possible that Klaus would have found a better sequence for White than the one illustrated here. _____________________________________________________________________________
But each Medcalf Defense structure in this game is far enough away from the edge of the board to allow Black to improve upon the basic pattern of the Defense.
If White continues to extend with 13.k4, then 14.r1115.o1016.p10 now looks like a solid Black win opportunity. But if instead White moves prematurely to block the primary pathway with either 13.r11 or 13.o10, then Black can instead make use of the potential alternate pathway that was used to set up the Defense with 14.n415.p416.p3, and this still looks like a probable Back win from here.
(2) This same approach also can be used to improve the SECOND OPPORTUNITY, even though closer to the edge of the Board, because there is just enough space for Black to play |14.e2015.g1916.g2117.i2018.j2019.k2120.l21, followed by either 21.m2222.f1523.i1624.h16 or 21.i1622.j2223.h2224.h23. White might still win this, but Black's position is clearly stronger here, under either alternative line of play, than it was after the original SECOND OPPORTUNITY sequence as shown above with an apparent Black loss.
Thanks for the credit, Pete. Knowing of this possible play helps one prepare a game in advance. If you are playing against it, you can lay the groundwork for defeating it. Seeing the opportunity for using it, one can play supportive moves. In fact, since it is now rather widely known, I usually do not use it early in a game, but will instead defer the move if a supporting move can be made.
For those wanting more information on the wins and losses when this defense is deployed, visit the Wetpaint wiki article created by Alan Hensel.
THE INVENTION OF THE MEDCALF DEFENSE
When he reviewed it later, this was the game that prompted Steven Medcalf to originally invent the Medcalf Defense. This was probably the best game I had ever played up to this time on Little Golem, but I still lost the game to Klaus (a very frequent occurrence!). Steven (on LG) later pointed out that I might well have won this game if I had been able to see how to apply a clever technique, which later became known as the Medcalf Defense.
I employed the Medcalf Defense in the championship game against David Bush during the 2006 World Boardgaming Convention championship game, its first known use in a live tournament, but still lost to David. ;-) You can see it employed here, in the corner of the board toward the upper left in the photo: http://www.mindspring.com/~alanh/twixt/wbc2006/wbc2006_twixt_final.jpg (I am on the left and playing Black; David Bush, playing red, is on the right; the photo is by Alan Hensel.)
Alan Hensel, who was observing the game at the time, thought I had made a serious mistake until he saw how it played out just a few moves later. David Bush quickly realized the potential of the technique, and was worried at first, but then recognized that he could use the red peg in the lower left of the photo as the resource he would need to still win the game.
Alan has prepared an excellent write up about the use of the Medcalf defense at: http://twixt.wetpaint.com/page/The+Medcalf+Defense
The first known use of this technique on LG was in game 469944: http://www.littlegolem.net/jsp/game/game.jsp?gid=469944&nmove=23 , not long after its invention.
Steven Medcalf himself employed it on LG almost at the same time in game 477915: http://www.littlegolem.net/jsp/game/game.jsp?gid=477915&nmove=14
The next two comments analyze the not just one, but TWO (!) different opportunities to have employed the Medcalf Defense within this game.
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FIRST OPPORTUNITY
After 5.s8 the Medcalf Defense could have been employed with 6.s6 7.q7 8.q5 9.o6 10.n6 11.m5 12.r11 13.o10 14.p10 15.m9 16.l7 17.j8 18.k8 19.k6 20.k9 for a possible win early in the game. Of course it is also always possible that Klaus would have found a better sequence for White than the one illustrated here.
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SECOND OPPORTUNITY
After 13.e18 the Medcalf Defense could have been employed for a second (!) time in this same game with
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... but this second possible use opportunity still looks like a win for White!
IMPROVEMENT OPPORTUNITIES
But each Medcalf Defense structure in this game is far enough away from the edge of the board to allow Black to improve upon the basic pattern of the Defense.
(1) Black can extend the line further than shown in FIRST OPPORTUNITY with |6.s6 7.q7 8.q5 9.o6 10.n6 11.m5 12.l5
If White continues to extend with 13.k4, then 14.r11 15.o10 16.p10 now looks like a solid Black win opportunity. But if instead White moves prematurely to block the primary pathway with either 13.r11 or 13.o10, then Black can instead make use of the potential alternate pathway that was used to set up the Defense with 14.n4 15.p4 16.p3, and this still looks like a probable Back win from here.
(2) This same approach also can be used to improve the SECOND OPPORTUNITY, even though closer to the edge of the Board, because there is just enough space for Black to play |14.e20 15.g19 16.g21 17.i20 18.j20 19.k21 20.l21, followed by either 21.m22 22.f15 23.i16 24.h16 or 21.i16 22.j22 23.h22 24.h23. White might still win this, but Black's position is clearly stronger here, under either alternative line of play, than it was after the original SECOND OPPORTUNITY sequence as shown above with an apparent Black loss.
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For those wanting more information on the wins and losses when this defense is deployed, visit the Wetpaint wiki article created by Alan Hensel.