YO
Worth 5 points before any premium square, and the 12th highest-scoring of 96 — tied with 21 others.
YO extends into 7 three-letter words, which is the 26th least extendable of 96 — tied with 7 others. That is the number worth memorising: a two-letter word is a place to put tiles, but a well-hooked one is a place to put them where the board stays open.
Every hook
No letter in front of YO makes a word.
- B→YOB
- D→YOD
- K→YOK
- M→YOM
- N→YON
- U→YOU
- W→YOW
Not all of them are equally reachable, which a bare count of 7 hides. YO hooks on 7 distinct letters, and the ones you are likeliest to be holding are N (36% of opening racks), D (26% of opening racks) and U (26% of opening racks). The rarest is K, at 7%.
How often you can actually play it
Out of an opening rack, 5.52% of the time you hold the letters for YO outright, the 27th least likely of 96 — tied with 10 others. Counting a blank as whichever letter is missing lifts that to 11.75%, though spending one of the two blanks on a two-letter word is rarely the play. Exact hypergeometrics over the 100-tile bag, not a simulation.
It reverses
YO backwards is OY, which is also good. That is how most of this list is actually learned — 46 of the 96 come in reversible pairs, so knowing one gets you the other free.