Children who enter school not yet reading need some systematic phonics to get them started, but cannot be expected to cope with the whole alphabet or more than a subset of phoneme-grapheme correspondences and grapheme-phoneme correspondences at that stage. So phonics schemes necessarily adopt some sequence for the introduction of graphemes and phonemes. The Letters and Sounds scheme began with "satpin," that is, those graphemes and their most frequent correspondences with phonemes, /s ae t p [near-close near-front unrounded vowel] n/, and the two most widely used British phonics schemes incorporate variants of that initial sequence. Yet why those graphemes and phonemes? This article traces "satpin" back to its origins in the 1960s in the work of Sally B. Childs and Aylett Royall Cox, American exponents of Orton-Gillingham methods. The article focuses upon a 1967 publication by Cox featuring a version of "satpin" and explains and explores its scientific basis. We then show both where Cox's insight has been influential (or not) in British literacy schemes and where authors of phonics materials have taken a different tack, or suggested alternative phonetic starting points. The phonetic analysis underlying Cox's rationale needs updating. When that is done, both it and the rediscovered original logic may suggest useful changes in the initial teaching sequence of phonemes and graphemes.