WO
Worth 5 points before any premium square, and the 12th highest-scoring of 96 — tied with 21 others.
WO extends into 10 three-letter words, which is the 45th most extendable of 96 — tied with 8 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
- T→TWO
- E→WOE
- G→WOG
- K→WOK
- N→WON
- O→WOO
- P→WOP
- S→WOS
- T→WOT
- W→WOW
Not all of them are equally reachable, which a bare count of 10 hides. WO hooks on 9 distinct letters, and the ones you are likeliest to be holding are E (60% of opening racks), O (45% of opening racks) and T (36% 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 WO 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
WO backwards is OW, 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.