user191: So we got identification-request for ID requests and music for, according to its description, anything about music. Supposedly ID requests too, but this is not exactly how tags work, right? What about instead of combining these tags in questions where someone asks to identify music, we use music-identification?
The tag identification-request is primarily used to identify anime or manga. Should music be included?
What are the pros and cons of both options? Which should we use when?

user1908: 
The tag identification-request is primarily used to identify anime or manga. Should music be included?

You are framing the question wrong. There are two questions to be asked here.

The tag identification-request is primarily used to identify anime or manga. Should it also be used for questions where OP has found a piece of music, devoid of context?

And the answer to this question is yes, of course. "I heard this song and I don't know what it's from" has all the hallmarks of a conventional identification request. 

The tag identification-request is primarily used to identify anime or manga. Should it also be used for questions where OP wants to know the name of a song that was used in a particular episode of some anime?

And the answer to this question is no, of course not, why would you even think that is reasonable?. "What's this song in episode 3 of anime X?" is no more an identification-request than "Why did A do B in episode 3 of anime X?" or "Who drew scene Q in episode 3 of anime X?". Those who believe otherwise clearly fail to understand how tags ought to work. 
(Prior art: We shouldn't use [identification-request] on questions that aren't really identification requests)

user1530: I think there needs to be some clarification here on what current identification-request questions are and their scope.
Let's look at the wiki:

For questions which ask about the identification of an anime/manga/character using a description; specific elements (like a character or song); or screenshots

This is currently how they are supposed to be used.
It also doesn't make much sense to keep the existing identification-request tag if we would want to split them up - as it will be confusing to users. If there is a consensus to get music-identification and et cetera, we should also get series-identification, x-identification, ...
I don't think this is the actual solution to our problem. From the original meta question:

I see why people are tagging these questions with identification-request - the asker wants something "identified", right? But this is a dangerous line of thinking. Should we tag Is Nadia voluntarily inspired by Castle in the Sky? with identification-request because the asker wants to "identify" the connection between Nadia and Castle in the Sky? What about The Kamisama Hajimemashita anime covers the manga up to what chapter? - doesn't the asker want to "identify" the chapter at which the anime ends? No, of course we shouldn't.

This problem still remains if we change this but it shifts from one tag to multiple - should we create a series-connection-identification tag? a  chapter-identification tag, does chapter ids fit in manga ids? ....
Instead I propose that there should be some clarification for when the id-request tag should be used. Whether that turns out to be for questions where the series is unknown,specific media elements, or some other decision.
For my actual opinion on splitting the tag up - I'm indifferent, but I don't want to do it for the wrong reasons

user7579: I agree with Toshinou-san that we need clarification about identification-request edge cases—not just for music, but also for questions that ask, for example, to explain a reference, like Who are these characters referenced in Chapter 4 of Spotted Flower? (which is tagged identification-request) and Who are all the girls fawning over Araragi? (which is just tagged monogatari-series). 
However, I don't think making another tag for music identification is a very good solution. As touched on a bit in the post senshin linked to, helping people find questions they can answer is a major purpose of tags. If you want to identify a song from Naruto, the person who knows is probably a Naruto expert. If you want to identify a song from Mamotte Shugogetten, the person who knows is probably an expert on Mamotte Shugogetten (if such a thing even exists). There probably isn't anyone on the site who's a "soundtrack expert" that can identify songs from both Naruto and Mamotte Shugogetten, but has no interest in other types of question on Naruto or Mamotte Shugogetten. (I can see such a person existing on Movies and TV—a music superfan who loves identifying songs that appear in movies and TV shows—but things are different in anime.)
Given that, I don't really see a clear purpose for a music-identification tag. I suppose it could help people who love Mamotte Shugogetten, but aren't familiar with the OST, to avoid music identification questions. But the titles are usually something like "What song plays at time 7:23 in Episode 19 of Mamotte Shugogetten?". And the music tag should be a good enough signal for that sort of thing on its own; my Gedankenexperimental expert can just look for questions tagged mamotte-shugogetten and not tagged music.
Tagging music identifications as identification-request has some of the same problems as the music-identification tag. We don't really have "identification experts"; id requests require either a good memory and a broad knowledge of anime, or the dumb luck to have seen and remembered whatever the OP is looking for and the reading skills to pick it out of their description. This is different from the knowledge needed to identify a song from a known series. My preferred solution would be just tagging music identifications as mamotte-shugogetten music. 

user1398: Let's analyze the pro and con of using identification-requestmusic vs. music-identification, in term of categorizing questions.
We have 3 categories of questions related to music:

Identification request for a series, with a piece of music as clue (answer contains both the series name and the track title)
Soundtrack identification where the series is known (answer contains the track title)
Other non-identification questions related to music

We observe that category 2 and 3 specify complementing sets of questions for a particular series: music identification questions and other music-related questions.
We would like to analyze the categorizing effect of tagging based on the following scenarios:

Search for category 1
Search for category 2
Search for category 3
Search for category 1 and 2 (all music identification questions)
Search for category 2, for a particular series (all soundtrack identification questions of a series)
Search for category 3, for a particular series/topic (all non-identification music questions of a series/topic)
Search for category 2 and 3, for a particular series (all music-related questions of a series)


Scheme 1a: With the previous scheme of tagging (before senshin's meta thread):
Tagging scheme:

Category 1 is tagged as identification-requestmusic
Category 2 is tagged as identification-requestmusic, plus series tag
Category 3 is tagged as music, plus appropriate tags.

Search queries for each scenario:

Scenario 1 and 2 can't be searched, since category 1 and 2 are both tagged identification-requestmusic, and differentiated with the existence of series tag, which can't be excluded in the search.
Scenario 3 can be found with [music] -[identification-request].
Scenario 4 can be found with [music][identification-request].
Scenario 5 can be found with [<series tag>][music][identification-request].
Scenario 6 can be found with [<series tag>][music] -[identification-request]
Scenario 7 can be found with [<series tag>][music]

Scheme 2a: With the current scheme of tagging (after senshin's meta thread):
Tagging scheme:

Category 1 is tagged as identification-requestmusic
Category 2 is tagged as music, plus series tag
Category 3 is tagged as music, plus appropriate tags.

(Same as above, except that category 2 is tagged as music only)
Search queries for each scenario:

Scenario 1 can be found with [music][identification-request]
Scenario 2 and 3 can't be searched, since category 2 and 3 are not distinguishable, as we only have music, plus series tag or other tags.
Scenario 4, 5, 6 are not searchable, since we can't tell apart questions in category 2 and 3.
Scenario 6 is only searchable for non-series-tag (like anime-production), with the observation that identification-request questions don't use those tags.
Scenario 7 can be found with [<series tag>][music]


Scheme 1b: Replace identification-requestmusic with music-identification for category 1 and 2, following the previous scheme of tagging soundtrack identification questions with identification-request)
Tagging scheme:

Category 1 is tagged as music-identification
Category 2 is tagged as music-identification, plus series tag
Category 3 is tagged as music, plus appropriate tags.

Search queries for each scenario:

Scenario 1 and 2 can't be searched, since category 1 and 2 are both tagged music-identification, and differentiated with the existence of series tag, which can't be excluded in the search.
Scenario 3 can be found with [music].
Scenario 4 can be found with [tag:music-identification].
Scenario 5 can be found with [<series tag>][music-identification].
Scenario 6 can be found with [<series tag>][music]
Scenario 7 can't be searched, since search syntax does not support A and (B or C).

The search syntax is simplified for some queries, compared to the queries in scheme 1a. However, scenario 7 is no longer searchable.
Scheme 2b: Replace identification-requestmusic with music-identification for category 1, following the current scheme of tagging category 2 without identification-request)
This scheme doesn't make sense, since the purpose of music-identification is to put questions in category 1 and 2 in the same basket. The search queries are more or less the same as scheme 2a. No problem is solved by doing this.

191: <p>So we got <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a> for ID requests and <a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a> for, according to its description, <em>anything</em> about music. Supposedly ID requests too, but this is not exactly how tags work, right? What about instead of combining these tags in questions where someone asks to identify music, we use <a href="https://anime.stackexchange.com/questions/tagged/music-identification" class="post-tag" title="show questions tagged &#39;music-identification&#39;" rel="tag">music-identification</a>?</p>

<p>The tag <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a> is primarily used to identify anime or manga. Should music be included?</p>

<p>What are the pros and cons of both options? Which should we use when?</p>
 1908: <blockquote>
  <p>The tag <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a> is primarily used to identify anime or manga. Should music be included?</p>
</blockquote>

<p>You are framing the question wrong. There are two questions to be asked here.</p>

<blockquote>
  <p>The tag <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a> is primarily used to identify anime or manga. Should it also be used for questions where OP has found a piece of music, devoid of context?</p>
</blockquote>

<p>And the answer to this question is <em>yes, of course</em>. "I heard this song and I don't know what it's from" has all the hallmarks of a conventional identification request. </p>

<blockquote>
  <p>The tag <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a> is primarily used to identify anime or manga. Should it also be used for questions where OP wants to know the name of a song that was used in a particular episode of some anime?</p>
</blockquote>

<p>And the answer to this question is <em>no, of course not, why would you even think that is reasonable?</em>. "What's this song in episode 3 of anime X?" is no more an <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a> than "Why did A do B in episode 3 of anime X?" or "Who drew scene Q in episode 3 of anime X?". Those who believe otherwise clearly fail to understand how tags ought to work. </p>

<p>(Prior art: <a href="https://anime.meta.stackexchange.com/q/2307/">We shouldn&#39;t use [identification-request] on questions that aren&#39;t really identification requests</a>)</p>
 1530: <p>I think there needs to be some clarification here on what current <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a> questions are and their scope.</p>

<p>Let's look at the wiki:</p>

<blockquote>
  <p>For questions which ask about the identification of an anime/manga/character using a description; specific elements (like a character or song); or screenshots</p>
</blockquote>

<p><strong>This is currently how they are supposed to be used.</strong></p>

<p>It also doesn't make much sense to keep the existing <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a> tag if we would want to split them up - as it will be confusing to users. If there is a consensus to get <a href="https://anime.stackexchange.com/questions/tagged/music-identification" class="post-tag" title="show questions tagged &#39;music-identification&#39;" rel="tag">music-identification</a> and et cetera, we should also get <a href="https://anime.stackexchange.com/questions/tagged/series-identification" class="post-tag" title="show questions tagged &#39;series-identification&#39;" rel="tag">series-identification</a>, <a href="https://anime.stackexchange.com/questions/tagged/x-identification" class="post-tag" title="show questions tagged &#39;x-identification&#39;" rel="tag">x-identification</a>, ...</p>

<p>I don't think this is the actual solution to our problem. From the original meta question:</p>

<blockquote>
  <p>I see why people are tagging these questions with identification-request - the asker wants something "identified", right? But this is a dangerous line of thinking. Should we tag Is Nadia voluntarily inspired by Castle in the Sky? with identification-request because the asker wants to "identify" the connection between Nadia and Castle in the Sky? What about The Kamisama Hajimemashita anime covers the manga up to what chapter? - doesn't the asker want to "identify" the chapter at which the anime ends? No, of course we shouldn't.</p>
</blockquote>

<p>This problem still remains if we change this but it shifts from one tag to multiple - <em>should we create a <a href="https://anime.stackexchange.com/questions/tagged/series-connection-identification" class="post-tag" title="show questions tagged &#39;series-connection-identification&#39;" rel="tag">series-connection-identification</a> tag? a  <a href="https://anime.stackexchange.com/questions/tagged/chapter-identification" class="post-tag" title="show questions tagged &#39;chapter-identification&#39;" rel="tag">chapter-identification</a> tag, does chapter ids fit in manga ids? ....</em></p>

<p>Instead I propose that there should be some <strong>clarification</strong> for when the <a href="https://anime.stackexchange.com/questions/tagged/id-request" class="post-tag" title="show questions tagged &#39;id-request&#39;" rel="tag">id-request</a> tag should be used. Whether that turns out to be for questions where the series is unknown,specific media elements, or some other decision.</p>

<p>For my actual opinion on splitting the tag up - I'm indifferent, but I don't want to do it for the wrong reasons</p>
 7579: <p>I agree with Toshinou-san that we need clarification about <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a> edge cases&mdash;not just for music, but also for questions that ask, for example, to explain a reference, like <a href="https://anime.stackexchange.com/q/4127/7579">Who are these characters referenced in Chapter 4 of Spotted Flower?</a> (which is tagged <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a>) and <a href="https://anime.stackexchange.com/q/17248/7579">Who are all the girls fawning over Araragi?</a> (which is just tagged <a href="https://anime.stackexchange.com/questions/tagged/monogatari-series" class="post-tag" title="show questions tagged &#39;monogatari-series&#39;" rel="tag">monogatari-series</a>). </p>

<p>However, I don't think making another tag for music identification is a very good solution. As touched on a bit in <a href="https://anime.meta.stackexchange.com/q/2307/7579">the post senshin linked to</a>, helping people find questions they can answer is a major purpose of tags. If you want to identify a song from Naruto, the person who knows is probably a Naruto expert. If you want to identify a song from <a href="https://en.wikipedia.org/wiki/Mamotte_Shugogetten" rel="nofollow noreferrer">Mamotte Shugogetten</a>, the person who knows is probably an expert on Mamotte Shugogetten (if such a thing even exists). There probably isn't anyone on the site who's a "soundtrack expert" that can identify songs from both Naruto and Mamotte Shugogetten, but has no interest in other types of question on Naruto or Mamotte Shugogetten. (I can see such a person existing on Movies and TV&mdash;a music superfan who loves identifying songs that appear in movies and TV shows&mdash;but <a href="https://anime.stackexchange.com/questions/24272/does-anybody-recognise-this-song-from-princess-kaguya/24290#comment34993_24272">things are different in anime</a>.)</p>

<p>Given that, I don't really see a clear purpose for a <a href="https://anime.stackexchange.com/questions/tagged/music-identification" class="post-tag" title="show questions tagged &#39;music-identification&#39;" rel="tag">music-identification</a> tag. I suppose it could help people who love Mamotte Shugogetten, but aren't familiar with the OST, to avoid music identification questions. But the titles are usually something like "What song plays at time 7:23 in Episode 19 of Mamotte Shugogetten?". And the <a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a> tag should be a good enough signal for that sort of thing on its own; my Gedankenexperimental expert can just look for questions tagged <a href="https://anime.stackexchange.com/questions/tagged/mamotte-shugogetten" class="post-tag" title="show questions tagged &#39;mamotte-shugogetten&#39;" rel="tag">mamotte-shugogetten</a> and not tagged <a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a>.</p>

<p>Tagging music identifications as <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a> has some of the same problems as the <a href="https://anime.stackexchange.com/questions/tagged/music-identification" class="post-tag" title="show questions tagged &#39;music-identification&#39;" rel="tag">music-identification</a> tag. We don't really have "identification experts"; id requests require either a good memory and a broad knowledge of anime, or the dumb luck to have seen and remembered whatever the OP is looking for and the reading skills to pick it out of their description. This is different from the knowledge needed to identify a song from a known series. My preferred solution would be just tagging music identifications as <a href="https://anime.stackexchange.com/questions/tagged/mamotte-shugogetten" class="post-tag" title="show questions tagged &#39;mamotte-shugogetten&#39;" rel="tag">mamotte-shugogetten</a> <a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a>. </p>
 1398: <p>Let's analyze the pro and con of using <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a><a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a> vs. <a href="https://anime.stackexchange.com/questions/tagged/music-identification" class="post-tag" title="show questions tagged &#39;music-identification&#39;" rel="tag">music-identification</a>, in term of categorizing questions.</p>

<p>We have 3 categories of questions related to music:</p>

<ol>
<li>Identification request for a series, with a piece of music as clue (answer contains both the series name and the track title)</li>
<li>Soundtrack identification where the series is known (answer contains the track title)</li>
<li>Other non-identification questions related to music</li>
</ol>

<p>We observe that category 2 and 3 specify complementing sets of questions for a particular series: music identification questions and other music-related questions.</p>

<p>We would like to analyze the categorizing effect of tagging based on the following scenarios:</p>

<ol>
<li>Search for category 1</li>
<li>Search for category 2</li>
<li>Search for category 3</li>
<li>Search for category 1 and 2 (all music identification questions)</li>
<li>Search for category 2, for a particular series (all soundtrack identification questions of a series)</li>
<li>Search for category 3, for a particular series/topic (all non-identification music questions of a series/topic)</li>
<li>Search for category 2 and 3, for a particular series (all music-related questions of a series)</li>
</ol>

<hr>

<h3>Scheme 1a: With the previous scheme of tagging (before <a href="https://anime.meta.stackexchange.com/questions/2307/we-shouldnt-use-identification-request-on-questions-that-arent-really-identi">senshin's meta thread</a>):</h3>

<p>Tagging scheme:</p>

<ul>
<li>Category 1 is tagged as <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a><a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a></li>
<li>Category 2 is tagged as <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a><a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a>, plus series tag</li>
<li>Category 3 is tagged as <a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a>, plus appropriate tags.</li>
</ul>

<p>Search queries for each scenario:</p>

<ul>
<li>Scenario 1 and 2 can't be searched, since category 1 and 2 are both tagged <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a><a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a>, and differentiated with the existence of series tag, which can't be excluded in the search.</li>
<li>Scenario 3 can be found with <code>[music] -[identification-request]</code>.</li>
<li>Scenario 4 can be found with <code>[music][identification-request]</code>.</li>
<li>Scenario 5 can be found with <code>[&lt;series tag&gt;][music][identification-request]</code>.</li>
<li>Scenario 6 can be found with <code>[&lt;series tag&gt;][music] -[identification-request]</code></li>
<li>Scenario 7 can be found with <code>[&lt;series tag&gt;][music]</code></li>
</ul>

<h3>Scheme 2a: With the current scheme of tagging (after <a href="https://anime.meta.stackexchange.com/questions/2307/we-shouldnt-use-identification-request-on-questions-that-arent-really-identi">senshin's meta thread</a>):</h3>

<p>Tagging scheme:</p>

<ul>
<li>Category 1 is tagged as <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a><a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a></li>
<li>Category 2 is tagged as <a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a>, plus series tag</li>
<li>Category 3 is tagged as <a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a>, plus appropriate tags.</li>
</ul>

<p>(Same as above, except that category 2 is tagged as <a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a> only)</p>

<p>Search queries for each scenario:</p>

<ul>
<li>Scenario 1 can be found with <code>[music][identification-request]</code></li>
<li>Scenario 2 and 3 can't be searched, since category 2 and 3 are not distinguishable, as we only have <a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a>, plus series tag or other tags.</li>
<li>Scenario 4, 5, 6 are not searchable, since we can't tell apart questions in category 2 and 3.</li>
<li>Scenario 6 is only searchable for non-series-tag (like <a href="https://anime.stackexchange.com/questions/tagged/anime-production" class="post-tag" title="show questions tagged &#39;anime-production&#39;" rel="tag">anime-production</a>), with the observation that <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a> questions don't use those tags.</li>
<li>Scenario 7 can be found with <code>[&lt;series tag&gt;][music]</code></li>
</ul>

<hr>

<h3>Scheme 1b: Replace <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a><a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a> with <a href="https://anime.stackexchange.com/questions/tagged/music-identification" class="post-tag" title="show questions tagged &#39;music-identification&#39;" rel="tag">music-identification</a> for category 1 and 2, following the previous scheme of tagging soundtrack identification questions with <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a>)</h3>

<p>Tagging scheme:</p>

<ul>
<li>Category 1 is tagged as <a href="https://anime.stackexchange.com/questions/tagged/music-identification" class="post-tag" title="show questions tagged &#39;music-identification&#39;" rel="tag">music-identification</a></li>
<li>Category 2 is tagged as <a href="https://anime.stackexchange.com/questions/tagged/music-identification" class="post-tag" title="show questions tagged &#39;music-identification&#39;" rel="tag">music-identification</a>, plus series tag</li>
<li>Category 3 is tagged as <a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a>, plus appropriate tags.</li>
</ul>

<p>Search queries for each scenario:</p>

<ul>
<li>Scenario 1 and 2 can't be searched, since category 1 and 2 are both tagged <a href="https://anime.stackexchange.com/questions/tagged/music-identification" class="post-tag" title="show questions tagged &#39;music-identification&#39;" rel="tag">music-identification</a>, and differentiated with the existence of series tag, which can't be excluded in the search.</li>
<li>Scenario 3 can be found with <code>[music]</code>.</li>
<li>Scenario 4 can be found with <code>[tag:music-identification]</code>.</li>
<li>Scenario 5 can be found with <code>[&lt;series tag&gt;][music-identification]</code>.</li>
<li>Scenario 6 can be found with <code>[&lt;series tag&gt;][music]</code></li>
<li>Scenario 7 can't be searched, since search syntax does not support <code>A and (B or C)</code>.</li>
</ul>

<p>The search syntax is simplified for some queries, compared to the queries in scheme 1a. However, scenario 7 is no longer searchable.</p>

<h3>Scheme 2b: Replace <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a><a href="https://anime.stackexchange.com/questions/tagged/music" class="post-tag" title="show questions tagged &#39;music&#39;" rel="tag">music</a> with <a href="https://anime.stackexchange.com/questions/tagged/music-identification" class="post-tag" title="show questions tagged &#39;music-identification&#39;" rel="tag">music-identification</a> for category 1, following the current scheme of tagging category 2 without <a href="https://anime.stackexchange.com/questions/tagged/identification-request" class="post-tag" title="show questions tagged &#39;identification-request&#39;" rel="tag">identification-request</a>)</h3>

<p>This scheme doesn't make sense, since the purpose of <a href="https://anime.stackexchange.com/questions/tagged/music-identification" class="post-tag" title="show questions tagged &#39;music-identification&#39;" rel="tag">music-identification</a> is to put questions in category 1 and 2 in the same basket. The search queries are more or less the same as scheme 2a. No problem is solved by doing this.</p>
