OP
Worth 4 points before any premium square, and the 34th highest-scoring of 96 — tied with 18 others.
OP extends into 14 three-letter words, which is the 19th most extendable of 96 — tied with 10 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
- B→BOP
- C→COP
- F→FOP
- H→HOP
- K→KOP
- L→LOP
- M→MOP
- P→POP
- S→SOP
- T→TOP
- W→WOP
- E→OPE
- S→OPS
- T→OPT
Not all of them are equally reachable, which a bare count of 14 hides. OP hooks on 12 distinct letters, and the ones you are likeliest to be holding are E (60% of opening racks), T (36% of opening racks) and L (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 OP 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.