Ten-Pin Bowling
Ten frames of ten-pin bowling for two to four players, each on their own lane, a frame each in turn. A delivery is where you stand, which arrow you aim at, how fast and how much hook; the physics rolls the ball, the pins fall as they fall, and the card keeps the score the way a bowling card does.
The rules
- Ten frames on your own lane. In each frame you bowl up to two balls at ten pins; the pins you knock down are your count, and a frame scores its count plus any bonus it earns.
- A strike is all ten pins with the first ball, and the frame scores ten plus your next two balls. A spare is all ten with the two balls, and the frame scores ten plus your next ball. An open frame scores what fell, and the card leaves a frame's total blank until its bonus balls are known.
- The tenth frame gives you a third ball after a strike or a spare, so that the bonus balls are bowled and counted. Twelve strikes is 300, the perfect game.
- A delivery is four things: where you stand on the approach, as a board counted from the right edge of the lane's thirty-nine boards; which board at the seven arrows you aim at; your speed, up to nine and a half metres a second; and your hook. The ball starts along the line from your stance through your target and the hook turns it left as it slows.
- A pin is down when the ball or another pin knocks it over, wherever it ends up: on the deck, in the gutter or in the pit. A pin nudged off its spot but still standing stays where it stands, and counts as standing.
- A ball in the gutter is a miss: it runs down the channel to the pit and touches no pin. After the first ball the fallen pins are cleared and the standing ones stay exactly where they stand for the second.
- You take a frame each in turn, each on your own lane: the seat before you bowls its frame out before you get a ball. A frame turns over when the last seat has finished it, and the scoreboard is the only thing you share.
- A split is a leave with the head pin down and a gap between two or more of the pins still standing; the card rings the count. It is a name, not a penalty: the spare is simply harder.
How a game ends
- After the tenth frame the highest total wins. Two seats level is a draw; at three or four seats the places share where the totals tie.
- A resignation or a missed deadline ends the game for everyone: that seat is placed last, and the others stand by their totals as they were.
Worth knowing before you start
- The pocket is the gap between the 1 and the 3 pin, for a ball hooking left. A ball that arrives there at a slight angle drives through the rack; stand around board 21, aim at the second arrow, and let the hook bring it back.
- Speed and hook trade against each other: a faster ball hooks less, so full hook at top speed is a different line from full hook at seven metres a second.
- A spare is a straight ball. Stand across the lane from the leave and roll through it; the hook is for the full rack.
- The card says it all: an X for a strike, a slash for a spare, a dash for nothing down, a ring round a split, three boxes in the tenth. Your total appears under a frame only once its bonus balls are known.
- The 7-10 is the famous split and it is nearly hopeless; when a split leaves one sure pin, take the sure pin.
What is different here
- A pin is a disc that slides on the deck, not a body that topples. It is down when the knock it took was faster than a quarter of a metre a second, and the picture lays it over the way it was pushed. Pins meet each other at a wider reach than their bellies, standing in for the sweep of a falling pin, so that the pin action reads right.
- There is no bowler, so there is no foul: no foot over the line, no lofted ball, no approach to walk. The stance is a slider, bounded to the lane's boards.
- There is no pinsetter to get wrong: no improperly set pins, no dead wood on the lane when you bowl, no provisional balls and no disputes. The rake sweeps between deliveries and a pin that stands stays where it stood.
- The lane, the rack and the pins are the USBC's measurements: sixty feet to the head pin, twelve inches between pin spots, ten pins on the rack, seven arrows and the approach dots where a house lane has them. The oil and the friction are the site's numbers, chosen so that a good line strikes about half the time.
- The same delivery is bowled at most twice running. The physics is exact, so a line that strikes would strike every time; the delivery after two identical ones must change the stance, the target, the speed or the hook, if only by a notch, and the page says so before you bowl it.
Nothing in a delivery is chance: the physics is run once, stored as it happened, and published in the log, and bin/verify-rolls re-simulates a whole game from the log. The seed decides only how well the bot bowls against you.
Ten-Pin Bowling terms
- A strike
- All ten pins down with the first ball of a frame. The frame scores ten plus the next two balls.
- A spare
- All ten pins down with the two balls of a frame. The frame scores ten plus the next ball.
- An open frame
- A frame that leaves a pin standing after both balls. It scores what fell.
- A split
- A leave with the head pin down and a gap between the pins still standing, such as the 7-10 or the 4-6. The card rings the count.
- The pocket
- The gap between the 1 and the 3 pin, where a hooking ball goes through the rack for a strike.
- The leave
- The pins still standing after the first ball, named by number: the 10, the 2-4-5-8.
- A board
- One of the planks the lane is made of, counted from the right edge. The arrows sit on boards 5, 10, 15, 20, 25, 30 and 35.