user224: "Pin" and "skewer" are fairly common terms in chess:

A pin is a situation where a piece cannot move without exposing a more valuable piece to attack. For example, the Ruy Lopez Opening features a black knight pinned (against the black king) by a white bishop after white's third move.

A skewer is when a piece is attacked and moving it would expose a less valuable piece to attack. An example would be a black rook attacking a white queen along a file with a white rook on the same file behind the queen.


However, I am unaware of a term applying to a similar situation in which the attacked piece is of equal value to the piece it is shielding, whether because they are two pieces of the same type (e.g. rooks) or the same value (bishop and knight, using "conventional" values of 3 pawns/points for both knights and bishops). Does such a term exist? If so, what is it? Or do we just use "pin" (or "skewer")?
The diagram shows an example with a white bishop attacking two black rooks along the same diagonal.  (The black pawn is to rule out the possible responses Ra5 and Rb5, which distract from the point of the example.)
r7/1r2k3/8/1p1BK3/8/8/8/8 w - - 0 1


user13674: Simply call it a "double attack".
The bishop is attacking the b7 rook directly and the a8 rook by x-ray.
Of course pins & skewers involve an x-ray. But there are many double attacks ; some do & some do not involve an x-ray.

user11071: I'm not aware of any terms. Maybe it is helpful to think instead of the purpose of the move:

pin: preventing a piece from moving by threatening to attack a piece behind it
skewer: forcing a piece to move, in order to attack the piece behind it

So whether you call a situation with a knight in front of a bishop (or rook in front of a rook like in your board) a "skewer" or a "pin" depends perhaps on what the primary intention is.
In your board position, I would say that the A8 rook is skewered and the B7 rook is pinned.

224: <p>&quot;Pin&quot; and &quot;skewer&quot; are fairly common terms in chess:</p>
<ul>
<li><p>A <em>pin</em> is a situation where a piece cannot move without exposing a more valuable piece to attack. For example, the Ruy Lopez Opening features a black knight pinned (against the black king) by a white bishop after white's third move.</p>
</li>
<li><p>A <em>skewer</em> is when a piece is attacked and moving it would expose a less valuable piece to attack. An example would be a black rook attacking a white queen along a file with a white rook on the same file behind the queen.</p>
</li>
</ul>
<p>However, I am unaware of a term applying to a similar situation in which the attacked piece is of equal value to the piece it is shielding, whether because they are two pieces of the same type (e.g. rooks) or the same value (bishop and knight, using &quot;conventional&quot; values of 3 pawns/points for both knights and bishops). Does such a term exist? If so, what is it? Or do we just use &quot;pin&quot; (or &quot;skewer&quot;)?</p>
<p>The diagram shows an example with a white bishop attacking two black rooks along the same diagonal.  (The black pawn is to rule out the possible responses Ra5 and Rb5, which distract from the point of the example.)</p>
<pre><code>r7/1r2k3/8/1p1BK3/8/8/8/8 w - - 0 1
</code></pre>
 13674: <p>Simply call it a &quot;<strong>double attack</strong>&quot;.
The bishop is attacking the b7 rook directly and the a8 rook by x-ray.
Of course pins &amp; skewers involve an x-ray. But there are many double attacks ; some do &amp; some do not involve an x-ray.</p>
 11071: <p>I'm not aware of any terms. Maybe it is helpful to think instead of the purpose of the move:</p>
<ul>
<li>pin: preventing a piece from moving by threatening to attack a piece behind it</li>
<li>skewer: forcing a piece to move, in order to attack the piece behind it</li>
</ul>
<p>So whether you call a situation with a knight in front of a bishop (or rook in front of a rook like in your board) a &quot;skewer&quot; or a &quot;pin&quot; depends perhaps on what the primary intention is.</p>
<p>In your board position, I would say that the A8 rook is skewered <em>and</em> the B7 rook is pinned.</p>
