String-Selection Order as Preconditioning for Sequential Automatic Guitar Tuning: A Center-Outward Moment-Balanced Sequence for Coupled String-Neck-Bridge Systems

This paper formulates string-selection order as a preconditioning route through the coupled string-neck-bridge field of a guitar during sequential automatic tuning. In a coupled mechanical system, each local tuning acceptance alters the tension field, affecting subsequent measurements. For a standard six-string guitar, a fixed center-outward moment-balanced route (4,3) -> (5,2) -> (6,1) is proposed to minimize intermediate asymmetric loading. Furthermore, a generalized, adaptive moment-minimizing rule is provided for mixed error signs and non-standard geometries. The primary observable for evaluating route efficiency is formulated as 'post-acceptance drift'—the cumulative displacement of previously accepted strings caused by subsequent tuning operations. This controller-level ordering policy aims to reduce intermediate rework before the final settled state is reached.