Duckpin bowling is a variation of 10-pin bowling. The balls used in duckpin bowling are 4-3/4 in (12 cm) to 5 in (12.7 cm) in diameter (which is slightly larger than a softball), weigh 3 lb 6 oz (1.5 kg) to 3 lb 12 oz (1.7 kg) each, and lack finger holes. They are thus significantly smaller than those used in ten-pin bowling but are slightly larger and heavier than those used in candlepin bowling. The pins, while arranged in a triangular fashion identical to that used in ten-pin bowling, are shorter, smaller, and lighter than their ten-pin equivalents which makes it more difficult to achieve a strike. For this reason (and similar to candlepin bowling), the bowler is allowed three rolls per frame (as opposed to the standard two rolls per frame in ten-pin bowling).
Duckpin bowling centers are located in Connecticut, Massachusetts, Rhode Island, Indiana (near downtown Indianapolis), Maryland (especially in the Baltimore area), Wisconsin, and in suburban Washington, D.C.. There is also one located in Potter, Nebraska, the only one of its kind west of the Mississippi. 
Duckpin bowling has rules similar to ten-pin bowling. In a 10-frame game, bowlers try to knock down pins in the fewest rolls per frame. Bowlers have three balls per frame, instead of two in ten-pin bowling, to knock over a set of 10 pins. If a bowler knocks down all 10 pins with their first roll in a frame, it is scored as a strike. If all the pins are knocked down in two rolls, the bowler has made a spare. If all the pins are knocked down in three rolls, the bowler gets 10 points, as in candlepins, with no bonus. If pins are still standing after the third ball, the bowler gets one point for each pin knocked down.
It is more challenging, but some find it more fun!
In the case of a strike, the bowler gets 10 points plus the total number of pins knocked down with the next two balls rolled, for a maximum of 30 points. In the case of a spare, the bowler gets 10 points plus the number of pins knocked down with the next ball, for a maximum of 20 points. If it takes three balls to knock down all 10 pins, the bowler gets 10 points, with no bonus. A bowler's final score is the sum of the points earned over 10 frames (a spare or strike in the tenth frame earns one or two rolls respectively). The maximum possible score is 300 points, which is accomplished by rolling 12 strikes in a row. According to the NDBC, the official high score in a sanctioned game is 279, rolled by Pete Signore Jr. in 1992.
The origin of the sport is a subject of some debate. One possible origin is that duckpin bowling began in Baltimore around 1900, at a bowling, billiards and pool hall owned by future baseball Hall of Famers John McGraw and Wilbert Robinson, both of the then Baltimore Orioles.
However, according to a 2005 baseball book by Howard W. Rosenberg (Cap Anson 3: Muggsy John McGraw and the Tricksters: Baseball's Fun Age of Rule Bending), an article from May 1894 in the Lowell Sun confirms the existence of duckpins. Rosenberg traced the story of crediting the origins of duckpins to McGraw and Robinson as far back as Shirley Povich of The Washington Post in the late 1930s.
A major hole in the origin of the whopper has since come to light. Now accessible on the Internet, thanks to the scanning in of old newspapers, is the Pittsburgh Press of March 3, 1929, which ran an article from Baltimore saying that Robinson "originated" the sport and also gave it its name. The article can be found on the Internet by searching for the following phrase: "Wilbert Robinson Claims He Invented Duckpins".
In 1985, a 130-plus-page publication called Duckpins: The Tenth Frame cited related Lowell, Mass., coverage of duckpin bowling in May 1894. Writing in that publication, Bob Tkacz, of Newington, Connecticut, noted finding articles showing that a duckpin tournament was being held in Lowell at that time. The 1985 publication is not readily available from any U.S. library, which explains why Tkacz's finding was easy to miss as the earliest known "in print" rebuttal of the Baltimore origin myth. Articles can be found in the Globe earlier than May 1894 showing the existence of the sport around Boston, before the 1880 invention of the candlepin bowling sport in Worcester took over after that time, eventually eliminating duckpin bowling centers in the immediate Boston metro area after World War II. According to Rosenberg, the earliest Globe reference to duckpins was on January 2, 1893.
Rosenberg's book methodically accounted for Baltimore newspaper reporting in late 1899 and early 1900, when the sport seemingly was invented in Baltimore (at the McGraw-Robinson center). Baltimore Sun next-day reporting seems to credit the center for introducing the sport to Baltimore the night before.
In 1982, the Women's National Duckpin Association was formed to give women a venue to compete in duckpins at a professional level. The organization conducts several tournaments yearly in New England and the Mid-Atlantic. The final tournament each year is called the Grand Prix.
In the late 1900's a variant called rubber band duckpins was introduced in the Pittsburgh, Pennsylvania area. The pins are circled with hard rubber bands to increase action and scoring. The rubber band version was invented by William Wuerthele of Pittsburgh, Pennsylvania. Wuerthele observed bowlers wasting their third ball as well as flying pins injuring pin boys. According to a defunct publication called "The Ducks", Wuerthele added the rubber band to increase scoring. The American Duckpin Congress was formed in the 1920s to govern the game of rubber band duckpins. The organization later became the American Rubber Band Duckpin Bowling Congress in 1945 and became an affiliate of the National Duckpin Bowling Congress. The rubber band game is almost extinct with most of the lanes located in private clubs. Rubber band duckpin is the only version of duckpin played in the province of Quebec. Bowlers tend to throw slowly with their fingers facing forward to give the ball backspin. There have been perfect games bowled in rubber band duckpin, including the largest duckpin prize ever won on television, C$50,000 in 1994. Since it is easier to knock down pins in rubber band duckpin, its rules are identical to those of standard ten-pin bowling.
See also 
- The Ducks Magazine, October, 1928, Pittsburgh Pennsylvania
- Duckpins.com - Duckpin bowling information and history.
- National Duckpin Bowling Congress
- Women's National Duckpin Association
- Duckpin Professional Bowlers Association (new URL)
- A July 7, 2007, feature story on duckpin bowling in the Press Box, a Baltimore sports weekly (with a sidebar on the right-hand side of the text, starting partially down the page, citing the refutation of Baltimore as the alleged origin of the sport of duckpin bowling)
- A duckpin bowling score calculator
- A Sherman duckpin pinspotter in action
- Frontside view of the Sherman pinspotter in action