Optimised timepiece movement

A mechanical timepiece movement comprising a strip resonator mechanism that includes at least one inertial element oscillating about a first pivot axis under the action of mechanical elastic return means comprising a plurality of flexible strips, fixed, on the one hand, directly or indirectly, to a structure of said resonator mechanism, and on the other hand, directly or indirectly, to said at least one inertial element, said resonator mechanism being coupled to a magnetic escapement mechanism, which includes at least one escape wheel set pivoting about a second pivot axis and subjected to a torque exerted by at least one source of energy, and said at least one inertial element including at least two first magnetized areas at the periphery thereof, arranged to cooperate directly with second magnetized areas comprised in one said escape wheel set and in partial superposition therewith in projection onto a projection plane perpendicular to said first pivot axis, wherein said at least one escape wheel set includes a plurality of said second tangential magnetized areas each arranged substantially tangentially, and each arranged to repel one of said first magnetized areas, and further wherein said movement includes isochronism correction means combining, on the one hand, said first magnetized areas of said at least one inertial element, and, on the other hand, compensating magnets on said at least one escape wheel set, each said compensating magnet being arranged in proximity to one said second nearby tangential magnetized area and producing a leakage field in a different direction from that of the field of said second nearby tangential magnetized area, and said leakage field intensity being low compared to that of the field of said second nearby tangential magnetized area, and said leakage field being dimensioned to interact with one of said first magnetized areas of said at least one inertial element and to produce a low variation in the operation of said resonator mechanism.