In our previous blog post we discussed various strategies for defining crossword entries, including simple synonyms, puns or jokes, and general pointers toward the relevant attributes of the answer. But we left out one of our favorite strategies, which is a clue that defines a word by reference to the clue itself.

For example, a clue can be written in a particular form or with specific verbal constraints that exemplify the answer. Our first endeavor along these lines was this one:    HAIKU  Recited aloud, an exalted, brilliant stroke—this clue, for instance (5)

More recently, we clued INVERSE thus:    Like “false” to “true,”    Or like this clue (7)

A clue can also make reference to the type of wordplay it uses. That can happen either in the definition part:    CHARADE  Drink later. First, burn this clue (7) or in the wordplay:    HINT  Harsh interrogation yields “It’s a hidden-word clue” (4)

Still another type of self-reference is one that simply invokes the existence of the puzzle itself, or the process that the solver is involved with. For example:    CLUE  This signal left within (4)    SOLVE  What you’re trying to do, primarily: send love all about (5)

This is not a technique that can be used very often, mostly because there aren’t that many words that can describe a crossword clue, and to a lesser extent because it’s a trick that would be spoiled by overuse. But whenever there’s an opportunity to bring this into play—when a grid entry suggests some quality or attribute that a clue might display—we generally consider the possibility.

For solvers, self-reference can be double-edged. On the one hand, it’s generally easy to spot—the phrase “this clue” is almost always present, and almost always a giveaway. On the other hand, any kind of self-referential wordplay has the potential to be a little mind-bending.

Which brings us to our favorite kind of self-reference, one that involves planting a deliberate flaw in the wordplay of a clue. Here are two examples:    ERRORLESS  Sorry, reels got tangled up—unlike this clue (9)    INCORRECT  …in baroque concert, like this clue? (9) (The ellipsis in that latter clue was there to join its surface to that of the preceding clue; see this post.)

These are clues (there’s another one in Puzzle 3285 which we won’t spoil here) that flirt with the famous paradox of Epimenides, the Cretan who declared that all Cretans were liars—including, by implication, himself. The clues only work… because they don’t.

What are your thoughts on self-referential clues? Please share your thoughts here, along with any quibbles, questions, kudos or complaints about the current puzzle or any previous puzzle. To comment (and see other readers’ comments), please click on this post’s title and scroll to the bottom of the resulting screen.

And here are three links: • The current puzzle • Our puzzle-solving guidelines • A Nation puzzle solver’s blog where you can ask for and offer hints, and where every one of our clues is explained in detail.