What it does
Tipcha is a mid-strength disjunctive whose job is to set up the major pause. You will almost never see Tipcha appear on its own. It always sits one word before either Etnachta (mid-verse pause) or Sof Pasuk (end of verse), preparing the reader for the bigger stop that's about to land.
Where it appears
Most verses contain at least one Tipcha; many contain two: one setting up the Etnachta in the middle, and one setting up the Sof Pasuk at the end. If you spot a Tipcha, look ahead one word: a major pause is coming.
How to remember it
Tipcha shares a root with tefach, meaning "handspan." Picture the reader extending a hand before the pause, signaling that something is about to stop. The mark itself is a short diagonal slash below the letter, like a small swept line under the word that says "almost there."
Example from the Torah
Bereishis 1:1
Tipcha sits on הַשָּׁמַ֖יִם, two words before the end of the verse. It sets up the Sof Pasuk on הָאָֽרֶץ. The same verse also opens with a Tipcha on בְּרֵאשִׁ֖ית, which set up the Etnachta on אֱלֹהִ֑ים. Two Tipchas, two major pauses. A textbook layout.
Hear the melody
A synthesized rendering of the melodic shape, not a vocal recording. For a baal koreh's voice on a full aliyah, PocketTorah is a great free resource.
Hand signal (simanim)
Often confused with
Tipcha and Mercha both look like diagonal slashes below the letter. The key difference is function: Tipcha is a disjunctive (it pauses). Mercha is a conjunctive (it leads forward into the next word). If a major stop follows the next word, it's Tipcha. Otherwise it's Mercha.