El peón blanco de F nunca pudo llegar a F7 pues no tuvo las piezas negras suficientes para comer
Illegal Position Contest!

El peón blanco de F nunca pudo llegar allí, pues no tuvo más piezas para comer.-
That's incorrect. White's h-pawn can reach f7 by capturing Black's missing bishop and knight.

Its impossible because of the following contradiction: White is missing only 1 piece which is the dark squared bishop. Black is missing 3 pieces. Whites a to f pawn haven't been moved. Whites G pawn is on f3, whites H pawn is on f7. Blacks a to d pawns are on a4 b3 c3 and d3. The white H pawn on f7 must have captured 2 pieces, the white g pawn on f3 one piece. Thus, all the missing black pieces are accounted for. But then how did the white H pawn get past the black f pawn? The only way is if blacks pawn on F6 is originally his E pawn and it captured whites missing piece on the F6 square. But that is impossible as the white dark squared bishop could have never left C1 as b and d pawn havent moved. The only way blacks DSB can be off the board is because blacks queen sweeped it of the backrank. So if the white DSB wasnt available for capture on f6 the pawnconstellation on the F file is impossible

dang the closest I got
the timer at the end is what makes it illegal
I'm going to rule this a successful proof of the position's illegality (the proof by CarpeAgricolamCaveEquum was incorrect, as your proof game shows). The position is illegal because Black is one move short of enough pawn moves on the queen side to make the position legal.
Congratulations. I thought it would take a lot longer for anyone to discover that the position is legal if the black pawn on h4 is placed on h3.
dang the closest I got
the timer at the end is what makes it illegal
I'm going to rule this a successful proof of the position's illegality (the proof by CarpeAgricolamCaveEquum was incorrect, as your proof game shows). The position is illegal because Black is one move short of enough pawn moves on the queen side to make the position legal.
Congratulations. I thought it would take a lot longer for anyone to discover that the position is legal if the black pawn on h4 is placed on h3.
The hardest thing about this is creating the position
Took me half an hour to make one lol

Took me half an hour to make one lol
I would call that quick work. Some people might object that finding a proof game for one position doesn't prove the illegality of a different position. For them, here is a more detailed illegality explanation.
White's f1 bishop can move after the g-pawn has captured the black queen or knight on f3. White's h-pawn can reach f7 by capturing Black's missing bishop and queen or knight. Once the final king-side formation has been reached, Black has no moves there, and all remaining moves will be by Black's a through e pawns. The black b or d pawn must have already moved a single step, to let Black's c8 bishop out to reach g8. The black e pawn must have already moved a single step to let the f8 bishop out to be captured by White's h-pawn. The f8 bishop can't get out through g7, because then White's h-pawn could not reach g6 to capture the black queen or knight on f7. So Black has at most 17 pawn moves remaining. But it takes White at least 18 moves to put the bishop on a8 and the remaining pieces on their final squares. So Black is one move short of enough pawn moves to make the position legal, and thus it is illegal.

Ten hours since the last post. I think it's time to work on a position that is not obviously illegal.
Explain why this position is illegal, regardless of the side to move.
Great one! I've never seen a time-based illegal position before.

If by time-based you mean based on available tempos, that applies to this position. Of course it's unrelated to any game timer.

Took me half an hour to make one lol
I would call that quick work. Some people might object that finding a proof game for one position doesn't prove the illegality of a different position. For them, here is a more detailed illegality explanation.
White's f1 bishop can move after the g-pawn has captured the black queen or knight on f3. White's h-pawn can reach f7 by capturing Black's missing bishop and queen or knight. Once the final king-side formation has been reached, Black has no moves there, and all remaining moves will be by Black's a through e pawns. The black b or d pawn must have already moved a single step, to let Black's c8 bishop out to reach g8. The black e pawn must have already moved a single step to let the f8 bishop out to be captured by White's h-pawn. The f8 bishop can't get out through g7, because then White's h-pawn could not reach g6 to capture the black queen or knight on f7. So Black has at most 17 pawn moves remaining. But it takes White at least 18 moves to put the bishop on a8 and the remaining pieces on their final squares. So Black is one move short of enough pawn moves to make the position legal, and thus it is illegal.
at the end position, all of blacks pieces can't move. that's why the time thing works.

at the end position, all of blacks pieces can't move. that's why the time thing works.
As I said, only Black's a through e pawns have moves at the end, and they're one short of having enough. I guess you could call that a "time thing" if you like.

A little off-topic, but here's an interesting position. All 16 White men against a lone king, and neither side has a legal move. Let's see how quickly you can get here.
A little off-topic, but here's an interesting position. All 16 White men against a lone king, and neither side has a legal move. Let's see how quickly you can get here.
Illegal position
15 captures and h pawn is useless
so...

A little off-topic, but here's an interesting position. All 16 White men against a lone king, and neither side has a legal move. Let's see how quickly you can get here.
Illegal position
15 captures and h pawn is useless
so...
So... promote it!

A little off-topic, but here's an interesting position. All 16 White men against a lone king, and neither side has a legal move. Let's see how quickly you can get here.
Illegal position
15 captures and h pawn is useless
so...
So... promote it!
ppl have blindspots in promotions

A little off-topic, but here's an interesting position. All 16 White men against a lone king, and neither side has a legal move. Let's see how quickly you can get here.
This'll set the bar:
El peón blanco de F nunca pudo llegar allí, pues no tuvo más piezas para comer.-