How it works
Find a box where a digit's remaining candidates all fall inside one row and one column crossing through it โ nowhere else in the box. That box has to place the digit somewhere in that row or that column. Now find a strong link for the same digit elsewhere: two cells on a line running the other way, one of them sharing the box's row or column. Whichever of those two ends up as the digit, the crossing cell where the box's other line meets the strong link's far line loses it โ either the far cell takes it directly (same line as the crossing cell), or the near cell does, filling the box's shared line and pushing the box's digit into its other line instead, which the crossing cell also shares.
Try it
No worked example for this one yet. It turns up rarely enough that no puzzle has needed it as its next step so far โ one will appear here as soon as a generated puzzle offers it.