[ketzo]

That sounds so fun. Honestly, I wonder how you could enforce that on more experienced chess players; is there a way to make a second move "forgetting" what you did first?

[vaniver]

"Logically depend" has an easy interpretation: the second move must be also be valid if performed before the first move. [You could do a harder variant where both moves must be legal simultaneously.]

[ajkjk]

I assume it just means that, for instance, you can't move the same piece twice, or for the second move to one only legal once the first occurs.