Memorizing, Understanding And Drawing Conjectures

At a job interview I’d set up two different positions. My interviewer asked me to come up with a lesson plan, or at least something that they could learn from. After quickly introducing ourselves we set those up (see below). Black’s arrangement is the same in both diagrams, but White’s one differs a little. In one he’s already castled while in the other he’s not, and the c2 pawn is occupying the c4 square.

Black can play e5

[fen flip=true csl=Yc4,Ye1 cal=Ye7e5]rnbq1rk1/ppp1ppbp/3p1np1/8/2PPP3/2N2N2/PP2BPPP/R1BQK2R b KQkq – 0 1[/fen]

If you know a little bit about the King’s Indian then you probably know why playing e7-e5 is fine here. White is controlling that square twice and you are defending it only once. However Black’s dark-squared Bishop is x-raying the h8-a1 diagonal. So if White goes pawn grabbing, Black will be able to play Nxe4, at the right moment, and get his pawn back with an equal position.

Black shouldn’t play e5

Why is Black unadvised to play that exact same move here ? Isn’t the g7 Bishop still there, ready to jump into the game at the right moment ? He surely is but White has castled and his c2 pawn is still on c2.

[pgn flip=true navigation_board=above]
[SetUp “1”]
[FEN “rnbq1rk1/ppp1ppbp/3p1np1/8/3PP3/2N2N2/PPP1BPPP/R1BQ1RK1 b – – 0 6”]
[PlyCount “9”]
[SourceVersionDate “2019.11.18”]

6… e5 7. dxe5 dxe5 8. Qxd8 Rxd8 9. Nxe5 Nxe4 10. Nxe4 Bxe5 {[%csl Rb8,
Rc8,Rf6,Yg1,Rg7,Rh6][%cal Gc2c3,Yc1g5,Ye2c4] Compared to the first diagram, where White’s King wouldn’t be castled and his c2 pawn would be on the c4 square, here White stands better. Black got his pawn back but Black is not quite developed yet and White’s pieces can get positioned optimaly. The fact that White’s c2 pawn is still on his starting square is a big deal. Not only
we can move it to c3 (which will protect the d4 square) but it also doesn’t
restrict our light’s square Bishop’s prospect.} *
[/pgn]