The present invention provides in combination, an intonated string nut and string locking mechanism for a musical string instrument with a fretted fingerboard where the combination intonated string nut and string locking mechanism includes a string nut fulcrum and a string locking means, where each string nut fulcrum may have a varying linear position in relation to each individual string in order to provide the optimum compensation amount for improving the consistency and production of in-tune musical notes during play for musical string instruments with fretted fingerboards.