3 is sometimes removed instead of the 4) the bag's weight is considerably reduced. Carrying only a driver, 3-wood, 4-hybrid, 5-7-9 irons, pitching and sand wedges, and a putter reduces the number of clubs in the bag to 9; this is a common load-out for a "Sunday bag" taken to the driving range or to an informal game. A skilled player can usually overcome the lesser selection of club lofts by reducing their swing speed on a lower-loft iron and/or placing the ball further forward in their stance to get the same carry distance and/or launch angle as the next higher loft number. Another increasingly common informal format is a deliberately low upper limit such as four clubs, or three clubs plus putter, with a typical load being a wood or hybrid, middle iron, wedge and putter, although often with significant variation between players with regards to which specific clubs are favored in each role. Regulations The ruling authorities of golf, The R&A (formerly part of The Royal and Ancient Golf Club of St Andrews) and the United States Golf Association (USGA), reserve the right to define what shapes and physical characteristics of clubs are permissible in tournament play. The current rules for club design, including the results of various rulings on clubs introduced for play, are defined in Appendix II of the Rules of Golf. The overarching principle of club design used by both authorities is defined in Appendix II-1a, which states: "The club must not be substantially different from the traditional and customary form and make. The club must be composed of a shaft and a head and it may also have material added to the shaft to enable the player to obtain a firm hold (see 3 below). All parts of the club must be fixed so that the club is one unit, and it must have no external attachments." In addition, Appendix II-4a states, regarding club heads, that "the club head must be generally plain in shape. All parts must be rigid, structural in nature and functional. The club head or its parts must not be designed to resemble any other object. It is not practicable to define 'plain in shape' precisely and comprehensively." These two rules are used as the basis for most of the more specific rules of Appendix II, including that no club may have a concave face (1931) and various rules defining