I think I'll participate in this round. Here's my 1st attempt - 30.5 moves:

nice, that actually looked cool

We're more than 2 days into round 5 (for which the position can be found in post #60), and the only try so far has been mine!   Are people already losing interest?! C'mon, there've only been 4 rounds so far, and one was almost too short to even be considered an actual round ;)

cobra, I think yours is optimal. It takes black at least 30 moves to get all his pieces to those positions, so the puzzle ends on white's 31st move with mate.

      8     knight moves

    13    pawn moves

     3     king moves (castling included)

     2     rook moves

     2    queen moves

+    2    bishop moves

_____

    30

........

I just wanted to see how quickly it could be done, Now that would be funny if it were sound, as in the moves. so I guess that guy wins.

 Omg, I feel like an idiot now.   I sort of just dashed off moves into the editor and then previewed it to make sure I had the right position. With that in mind, it never even occurred to me that my 1st attempt could be optimal - I actually spent some time yesterday trying for a faster result!

Needless to say, you're completely right - guess that means round 5 is over.

Having already held us up for 2 whole days, I hope no one minds if I try to move things along by forging ahead with the next position. Here it is: 

Btw, I would like to clarify the rule stated in post #50, which may have been misinterpretted. I said that the problem poster could not participate, which is true. However, everyone else is eligible to win that round, regardless of how many previous rounds they have won. Of course, it is possible that nobody actually misunderstood that, but I want to be sure, since none of the past winners so far have attempted for a 2nd victory.

Illegal. how did the White bishop get to c8? The e or g pawn was not moved. The only way is for the b pawn to promote. But it would have to promote on a8, since b8 is a dark colored square. And it could not get to a8 unless it took blacks a pawn, but Blacks a pawn is on a3. So this position shouldbe declared null and void.

And since I found the optimal splution- infinity moves- here is my position.

 The position is legal. That's all I can say without giving out unfair hints, but careful considerations were made while creating this position, and I can guarantee that it is reachable.

The pawn captured a piece, and then promoted Dumb butt

EDIT: For some reason the game won't display correctly. Never mind, someone found a quicker solution in the meantime anyway...

Solution is Qe8-c6,only move for black is Qh1xc6,and then white check mate with Qc5,and also Qc6#

Hey, all. Apologies for not posting anything here in a while, but I've been extremely busy this past week and just haven't had any spare time :( 

77 ain't bad for that position. Keep in mind that an indefinite number of attempts are allowed for every position, so you could always try again before the end of the week (although time expires for this position in less than 24 hours). And too bad about the diagram - I've had that happen to me before, and it can be kind of annoying. Better luck next time.

Awesome! :) I haven't actually tried it myself, but I seriously doubt I could get to the position in less than 65 moves. In fact, it won't surprise me if no one is able to beat that, especially considering that almost 6 days have gone by with no improvements, with less than 1 day remaining. Anything could happen, though...

69 moves is very impressive, considering how difficult this position is to reach efficiently. However, browni3141 has posted a 65-mover, which means you'll need an even faster result to win. You still have almost a day - good luck!

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By the way, I noticed that all three proof games for round 6 were submitted within the first six hours, which seems a bit imbalanced. I might need to consider reducing the 1-week interval to maybe a 3- or 4-day interval (or perhaps even just a 1-day interval) at some point. Could everyone let me know what their opinion is on this? Thanks :)

 I think this works, but am not 100% sure whether the c4 and b5 pawns in the final position count as "passed" pawns, strictly speaking. If not, then please just post the solution, as I can't really be bothered to spend any more time on this puzzle than I already have.