user23820: There is a tactical motif I call "cocking the gun" which I have never seen explicitly mentioned. It happens when you prepare a discovered attack. See the following board. Is there an official name for this tactical motif?
From a Lichess puzzle
[Event "Cocking the gun"]
[Date "2020.07.25"]
[Round "-"]
[White "?"]
[Black "?"]
[Result "*"]
[SetUp "1"]
[FEN "5rk1/1p1q3p/p2pp1p1/2p5/4P1QP/2PP2b1/PP2Br2/2KR3R b - - 0 1"]

1... Rg2 2.Rdf1 Bf4+ 3.Rxf4 Rxg4


user7297: In Dutch, the two attacking pieces involved in a discovered attack (or the two defending ones in a pin, which is basically the flip side of a discovered attack) are called 'kopstuk' and 'staartstuk', literally translated 'head piece' (the black bishop) and 'tail piece' (the black rook). Preparing a discovered attack like this is called 'staartstuk plaatsen', literally translated 'putting the tail piece in place'. I think it has been coined in the official Dutch method for teaching chess which has been used widely since the 1990's, so many younger and middle-aged players here know the term.
I'm not sure if there's even a well-established (let alone official) English terminology for the 'tail piece'. Wikipedia doesn't mention it. Perhaps 'hidden piece' makes sense? Then you'd be 'putting the hidden piece in place', but as you can see, this is far from being official. I like your own phrase better.

user10380: This is called a battery.
Hooper & Whyld's The Oxford Companion to Chess says "battery" is "a problem term for one of the two kinds of ambush: a line-piece would command a line if another man of the same colour were moved off that line. Discovered checks arise from this kind of ambush. ... Players occasionally use the word 'battery' to describe doubled or tripled line-pieces; [problem] composers rarely use the word in this sense."
That book says that ambush is a term for a situation where a line-piece would command a line if another man [of no matter which colour] were moved off that line.
Sometimes these terms are used: rear piece for the piece whose attack line gets opened/discovered, and front piece/unit for the one that moves to open this line.
Problemists don't need the word battery to cover situations where the two pieces defend each other: they have other terms such as Turton doubling and Zepler doubling, depending on how the pieces move once they are on the same line.

23820: <p>There is a tactical motif I call &quot;cocking the gun&quot; which I have never seen explicitly mentioned. It happens when you prepare a discovered attack. See the following board. Is there an official name for this tactical motif?</p>
<p>From a <a href="https://lichess.org/training/77771" rel="nofollow noreferrer">Lichess puzzle</a></p>
<pre><code>[Event &quot;Cocking the gun&quot;]
[Date &quot;2020.07.25&quot;]
[Round &quot;-&quot;]
[White &quot;?&quot;]
[Black &quot;?&quot;]
[Result &quot;*&quot;]
[SetUp &quot;1&quot;]
[FEN &quot;5rk1/1p1q3p/p2pp1p1/2p5/4P1QP/2PP2b1/PP2Br2/2KR3R b - - 0 1&quot;]

1... Rg2 2.Rdf1 Bf4+ 3.Rxf4 Rxg4
</code></pre>
 7297: <p>In Dutch, the two attacking pieces involved in a discovered attack (or the two defending ones in a pin, which is basically the flip side of a discovered attack) are called 'kopstuk' and 'staartstuk', literally translated 'head piece' (the black bishop) and 'tail piece' (the black rook). Preparing a discovered attack like this is called 'staartstuk plaatsen', literally translated 'putting the tail piece in place'. I <em>think</em> it has been coined in the <a href="https://nl.wikipedia.org/wiki/Stappenmethode" rel="nofollow noreferrer">official Dutch method for teaching chess</a> which has been used widely since the 1990's, so many younger and middle-aged players here know the term.</p>
<p>I'm not sure if there's even a well-established (let alone official) English terminology for the 'tail piece'. <a href="https://en.wikipedia.org/wiki/Discovered_attack" rel="nofollow noreferrer">Wikipedia</a> doesn't mention it. Perhaps 'hidden piece' makes sense? Then you'd be 'putting the hidden piece in place', but as you can see, this is far from being official. I like your own phrase better.</p>
 10380: <p>This is called a <strong>battery</strong>.</p>
<p>Hooper &amp; Whyld's <em>The Oxford Companion to Chess</em> says &quot;<strong>battery</strong>&quot; is &quot;a problem term for one of the two kinds of ambush: a line-piece would command a line if another man of the same colour were moved off that line. Discovered checks arise from this kind of ambush. ... Players occasionally use the word '<a href="https://en.wikipedia.org/wiki/Battery_(chess)" rel="nofollow noreferrer">battery</a>' to describe doubled or tripled line-pieces; [problem] composers rarely use the word in this sense.&quot;</p>
<p>That book says that <strong>ambush</strong> is a term for a situation where a line-piece would command a line if another man [of no matter which colour] were moved off that line.</p>
<p>Sometimes these terms are used: <strong>rear piece</strong> for the piece whose attack line gets opened/discovered, and <strong>front piece/unit</strong> for the one that moves to open this line.</p>
<p>Problemists don't need the word <strong>battery</strong> to cover situations where the two pieces defend each other: they have other terms such as <a href="https://en.wikipedia.org/wiki/Turton_doubling" rel="nofollow noreferrer">Turton doubling</a> and <a href="https://en.wikipedia.org/wiki/Zepler_doubling" rel="nofollow noreferrer">Zepler doubling</a>, depending on how the pieces move once they are on the same line.</p>
