For example, if neither player realise the Check and continue playing regardless, does that invalidate the whole game?
During a friendly one might argue that it doesn’t matter.
Wizard’s Dwellings follow a similar principle, but whence formed without an announcement, the Check may then be bypassed for the benefit of either player.
The rule here, is that Check by a Wizard’s Dwelling is only valid if it’s announced and most especially in the case of Unintentional Self Check.
In this example position, Black has just played 1. … Nxd4, capturing a Pawn and threatening White’s Rook on f3. Thus now White has just played 2. Rd3.
White believes he has trapped Black’s Knight and that he is therefore about to gain material.
Yet unawares, by moving his Rook to d3 White has actually created a Wizard’s Dwelling, in turn empowering Black’s Knight to be delivering Check by Wizard… and also forking the e1 Rook.
As such, the move 2. Rd3 is actually an illegal move. It would not be allowed by a judge and certainly not by a computer algorithm.
Herewith, in a scenario such as this, it is the obligation of the opponent to announce the Check and thus the illegality of the move just made.
In this example, if Black does not see or realise that a Wizard’s Dwelling has been created, then there is no Check to announce and it is merely his own positional loss.
If on the other hand, Black does realise the Wizard’s Dwelling, then he may either:
- Announce the Check and declare the move illegal.
- Ignore the Check but capture the Rook all the same.
Black may not capture the King because:
- Check was not announced or thus valid.
- Capture of the King is forbidden.
Here then we can see how Wizard’s Dwellings can be a most interesting workhorse regardless of their complications.
I hope this article clarifies Unintentional Self Check from a Wizard’s Dwelling.
The Wizard’s Dwelling & The Law Of The Folly © Simon Jepps