SPEAKER 1: All right, let's have a look at non-threatening.
So non-threatening we are given a chessboard
with a bunch of letters on it and several pieces already placed
on the board, one queen and the eight ponds.
And we have these seven pieces remaining indicated at the bottom there.
And apparently our goal is to find a way to safely place all of the pieces,
so that none of them are quote, unquote threatened,
which means basically they're subject to attack by that piece based
on the rules of chess.
Now of course, all the pieces in this are white.
There's not actually two opponents going on, so
think of this more of like a civil war where the pieces are possibly
going to be able to attack each other even though they're all
on the same side.
So the first thing that you might want to do in this puzzle is figure out
where pieces cannot possibly go based on the chess pieces that are already
placed on the board.
Because by placing them in any of those spaces,
they would already be threatened or subject to attack by some other piece.
So for example, Queens as you may know are the most powerful piece in chess.
They can move any number of spaces in any direction, which
means putting pieces in any of these squares
would immediately put them under threat, because the queen could
move to any of those squares freely and could attack any piece in any of them.
So we can rule all of those out.
Additionally, pawns, the pawns can only generally move forward in chess.
They attack diagonally forward, which is, kind of,
a strange quirk of that piece.
And so we can also eliminate any of the two squares, or some of these pawns
are right on the edge of the board so we might not be able to eliminate them.
But any of the two squares diagonally in front
of any of the pawns, which means we can also eliminate any of these squares
as well.
So we know right out the gate that we can't possibly
put pieces in any of those spaces.
So where to go from here.
Well, this is really going to be a game of trial and error and logic.
And there are so many ways to approach solving this
that we're actually just going to, kind of, generally
go over some strategies to approach this,
and then we'll just kind of hone in on the answer.
So for example, the easiest ones to probably figure out
are the rooks, which are these two pieces here.
Rooks, as you may know, can attack similar to the queen,
but they can't go diagonally.
So they can move up and down or left and right any number of positions.
Now if we look at the rows and columns on the board that currently
have no other piece in them, that really only leaves four possible spots
for these rooks to go.
And really they actually have to exist in either of these pairs,
either the t and the s or the w and the e.
Because, otherwise, then if we put them in the same column or the same row,
they could attack each other, which would make them no longer--
they'd be threatened.
So they wouldn't be non-threatened.
So we know that the rook's have to go there
for sure in one-- in some of those squares, which
allows us to actually eliminate all of these squares
as well as possible locations.
Because regardless, there's going to be one rook in one of those columns,
one rook in the other, and similarly one room in one of those rows,
one rook in the other.
So that omits all of those other squares as well.
From here you just, kind of, need to figure out where other pieces could go.
So for example, if we take a look at the bishops here,
bishops are like rook's except they only attack diagonally.
So they can go as many pieces as they want, but only along a diagonal.
And if you take a look at what's left on the board,
these are the only places that rook's could go.
The night's attack in an L-shape.
I don't have them on the slides here, but similarly you
could figure out where they could possibly
go to not end up in a red square and not capture some other piece.
And the king is similar to the queen, except it can only
go one square around where it is, but can attack in any direction.
So based on that information, applying some logic and some practice
and just guessing, you can figure out that ultimately the pieces that-- well,
the places where we want to put the pieces are here.
And if we do that now, all 16 pieces from the white side
are not threatening each other.
And if we look at the letters that are underneath those squares
and read those again from left to right, top to bottom, we get the word welcome.
And that was the answer to non-threatening.