If unsuccessful, the shot disc is "fouled" and removed from the board, along with any of the player's other discs that were moved during the shot. When there are no enemy discs on the board, many (but not all) rules also state that a player must shoot for the centre of the board, and a shot disc must finish either completely inside the 15-point guarded ring line, or (depending on the specifics of the rules) be inside or touching this line. This is often called the "no hiding" rule, since it prevents players from placing their first shots where their opponent must traverse completely though the guarded centre ring to hit them and avoid fouling. When playing without this rule, a player may generally make any shot desired, and as long as a disc remains completely inside the outer line of the playfield, it remains on the board. During any shot, any disc that falls completely into the recessed central "20" hole (a.k.a. the "Toad" or "Dukie") is removed from play, and counts as twenty points for the owner of the disc at the end of the round, assuming the shot is valid. Scoring occurs after all pieces (generally 12 per player or team) have been played, and is differential: i.e., the player or team with higher score is awarded the difference between the higher and lower scores for the round, thus only one team or player each round gains points. Play continues until a predetermined winning score is reached. The earliest known crokinole board was made by craftsman Eckhardt Wettlaufer in 1876 in Perth County, Ontario, Canada. It is said Wettlaufer crafted the board as a fifth birthday present for his son Adam, which is now part of the collection at the Joseph Schneider Haus, a national historic site in Kitchener, Ontario, with a focus on Germanic folk art. Several other home-made boards dating from southwestern Ontario in the 1870s have been discovered since the 1990s. A board game similar to crokinole was patented on 20 April 1880 by Joshua K. Ingalls (US Patent No. 226,615)  Crokinole is often believed to be of Mennonite or Amish origins, but there is no factual data to support such a claim. The reason for this misconception may be due to its popularity in Mennonite and Amish groups. The game was viewed as a rather innocuous pastime – unlike the perception that diversions such as card playing or dancing were considered "works of the Devil" as held by many 19th-century Protestant groups.