used a manual from 1940, TM 20–250 Field Music Technical Manual, that clearly echoes Smith and Safranek. The Marine Corps had a competing manual, essentially mirroring Sousa but updated in 1942, Manual for Drummers, Trumpeters, and Fifers. Later in the 20th century there were several notable variations and extensions of rudimental drumming from teachers like Charles Wilcoxon, author of All-American Drummer and Modern Rudimental Swing Solos, and Alan Dawson, whose "Rudimental Ritual" was popular at Berklee College of Music in the 1970s. Drum Corps International was founded in 1971 bringing together drum corps from around North America to compete, some of which had been in existence since the 1930s or 1940s (though many others were formed as late as the mid-1960s). From the outset, the drummers steadily expanded the rudimental vocabulary from the traditional American military and NARD repertoire to include Swiss rudiments as well as Hybrid rudiments that combined elements of multiple unrelated rudiments into new, more complex patterns. In 1984, a Percussive Arts Society committee led by Jay Wanamaker reorganized, and reinterpreted, the NARD 26 and added another 14 to form the current 40 International Snare Drum Rudiments. Beginning in the early 1990s, rudimental instruction began to focus heavily on hybrid rudiments. Edward Freytag's 1993 Rudimental Cookbook and Dennis Delucia's 1995 Percussion Discussion both feature significant hybrid rudiment instruction. This trend continued into the 21st century with John Wooton's 2010 Rudimental Remedies, Bill Bachman's 2010 Rudimental Logic, and Ryan Bloom's 2019 Encyclopedia Rudimentia significantly focusing on hybrid corps-style rudiments as well as older standards. Present day In the 21st century there are four principal rudimental drumming cultures: Swiss Basler Trommeln, Scottish pipe drumming, Anglo-American ancient drumming, and American modern drumming (or DCI hybrid drumming). Other organized rudimental systems include the French, Dutch, German (Prussian), , , Bavarian, Austro-Hungarian, Italian, Belgian, , , Swiss Ordonnanz Trommel (non-Basel, poorly understood outside of Switzerland) systems, which are still studied and performed on a small scale in their home countries. There is also a distinct historic Spanish rudimental culture, though this system is no longer widely used, as well as a similarly defunct Sicilian system. Recently, the International Association of Traditional Drummers (IATD) has been working to once again promote the 26 NARD rudiments of 1933 (1870 Strube list of 25 plus 1). One of the chief issues the IATD has with the PAS 40 is the "Swiss influence," though only eight