3-434: The Kaplan–Sheinwold (or "K-S") bidding system was developed and popularized by Edgar Kaplan and Alfred Sheinwold during their partnership, which flourished during the 1950s and 1960s. K-S is one of many natural systems . The system was definitively described in their 1958 book How to Play Winning Bridge and later revised and retitled to The Kaplan-Sheinwold System of Winning Bridge in 1963. Kaplan–Sheinwold and
6-524: A system closely modeled on K-S, with loads of gadgets. In the late 1960s, the Precision Club system grafted a strong, forcing opening of 1 ♣ onto K-S, in effect following earlier suggestions by Marshall Miles that five-card majors and the weak no trump be added to the Schenken system . Kaplan viewed Precision with distaste, noting the disadvantages, both theoretical and at-the-table, of combining
9-637: The Roth-Stone system were the two most influential challengers to Standard American bidding in the US in the 1950s, 1960s, and 1970s. Although K-S is not frequently played in its original form in the 21st century, many of its features (though not the 12–14 point 1NT opening) survive in the popular 2/1 Game Forcing system. Additionally, a few elements of Kaplan–Sheinwold (notably Five-Card Majors) have become accepted as part of Standard American practice. Among modern experts, Chip Martel and Lew Stansby play
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