In this puzzle, the goal is to play the best blue move (just one) on the current turn to secure a huge zone for blue (and ultimately red as well) on the top. As well as playing the move, you should make sure you understand WHY the move is very good. Ultimately I will post the solution as well as a separate file with an explanation about why the move is effective, exploring a few lines of play .
The pentobi file with the problem is here (link: http://dl.dropbox.com/u/27727822/Puzzles/11SecureADCCZ/SecureADCCZ-Problem.blksgf).
The pentobi file with just the next move (the solution) is here (link: https://dl.dropboxusercontent.com/u/27727822/Puzzles/11SecureADCCZ/SecureADCCZ-Solution.blksgf).
I also created a pentobi file where I explain the solution, and play out two lines from there, which can be found here (link: https://dl.dropboxusercontent.com/u/27727822/Puzzles/11SecureADCCZ/SecureADCCZ-Solution-Explanation.blksgf)
There are two hints hidden below, click (separately) to see them: