I gave the onepocket.org rules a re-read, and read the WPA rules. Here are some interesting differences I noticed:
- No mention of re-rack option for balls pocketed on the break. Some form of this is pretty much always used these days in my experience matching up. Pretty sure DCC uses it, too.
- I didn't see any mention of jump cues, which are generally not allowed in one pocket. That could seriously change the strategy of "doubling up" an opponent on the head rail.
- It seems that the WPA rules don't allow the possibility of pocketing an opponents ball while jumping the cue ball off the table for the pocketed ball to be re-spotted. This is sometimes attempted when following the ball in is more difficult. Are there any reasons in particular for this difference? I personally like having this option.
- Seems like "base of the ball" rules are in effect instead of "full ball" rules for ball in hand behind the head string. This applies to all games, but it's not clear to me what the WPA rules are for behind the line play. I'd like for "on or below the head string" in 6.10 and "crosses the head string" in 6.11 to be defined more clearly. I assume the base of the cue ball is the relevant point in both cases.
Speaking of..
Maybe "the lowest point of the cue ball" is a more precise way to phrase this. "Center" is pretty good, but it has an overloaded use for tip placement, which might get confusing. Downside of "lowest" is we have to agree which way up is.