Here is a typical position of the Medcalf defense, as described by Alan Hensel in his “article”:http://twixt.wikifoundry.com/page/The+Medcalf+Defense on Wikifoundry.

!http://cf.geekdo-images.com/images/pic2339333.png!

The point is, if black plays E6, white can play E10.

My question is, instead of E6, what about black D4

!http://cf.geekdo-images.com/images/pic2339334.png!

What can white do?

G4

\|1.e5 2.g5 3.g9 4.k8 5.u20 6.d4 7.g4 8.e6 9.i8 10.i4 11.k7 12.n4 13.l4 14.k5 15.m6 16.l3 17.p5 18.q3

And it depends on the pieces on the right side …

Okay sure, but quoting from the above linked article, “Of course, the effectiveness of this position depends on White's ability to connect the e10-g9 group to the bottom side of the board. Some supporting white pegs are necessary.” But if black chooses this variation, it is white's ability to connect to the top which will require supporting pegs outside of the quarter board region.

Alan also wrote “There are too many variations to address in this space. Sometimes this defense is successful and sometimes not, depending on the surrounding pegs, as illustrated by these examples of the Medcalf Defense in actual games:” followed by a list of 10 links to LG games. Here are links to those same 10 games on Alan's analysis site.

“Pete versus Maciej”:http://twixt-commentator.duckdns.org/game/469944 Medcalf defense by white. Black won anyway, but could have won more quickly with my variation. I placed a comment there.

“Pete versus passenger”:http://twixt-commentator.duckdns.org/game/471473 Medcalf by white on move 11. This is closer to the corner, and my idea does not work, because of Florian's variation.

“Alan versus Klaus”:http://twixt-commentator.duckdns.org/game/583709 The Medcalf by white on move 7. Black won anyway, and it is too early in that game to say for sure that my “bust move” would have really been any better, but it was available as a resource for black all the same.

“Alan versus Tim”:http://twixt-commentator.duckdns.org/game/592693 This is further from the corner, and Florian's variation comes out a winner against my bust move, but there was another way to beat the Medcalf which I attempt to demonstrate in a comment on that page.

“Axel vs. Pete”:http://twixt-commentator.duckdns.org/game/600814 Medcalf by black on move 12. This is closer to the corner, and my idea does not work.

“Axel vs. Pete”:http://twixt-commentator.duckdns.org/game/603069 Medcalf by black on move 28. Again, too close to the corner for my idea to work.

“Axel vs. Pete”:http://twixt-commentator.duckdns.org/game/622478 Medcalf by White on move 13. My other way to beat the Medcalf looks good to me. I posted a comment.

“Pete vs. Axel”:http://twixt-commentator.duckdns.org/game/631331 Medcalf by black on move 16. White busted the Medcalf his own way.

“myself vs. Kd Hoffman”:http://cf.geekdo-images.com/images/pic2339630.png Medcalf by black on move 8. It's too early to be sure, but my bust move was a resource I might have been able to use.

Referring once again to the diagram in my initial post, here is my other way to beat the Medcalf. After F7 E10 i10 we get this position:

!http://cf.geekdo-images.com/images/pic2339630.png!

Black's i10 peg might be better positioned to connect to the left wall than a black peg on i9 would be.

In summary, NO the Medcalf is not busted, but my two ideas should definitely be considered when your opponent uses it against you.

Oh, and please bust my analysis if you can!

Yeah you are right, the Medcalf is an interesting possibility but there are some counters, your D4 is an interesting one and it seems that white will need a piece on the right side.

I posted some things on the commentator for you (-;

Nice to see such interesting conversations about this defense.  We all know that Twixt ALWAYS depends on the position and what other pegs may influence it.

The Medcalf defense is important enough to understand how it can be used and how it can be defeated as any other attack/defense.