In guitar performance, fingering is an important factor, and complicated. In particular, the fingering of the left hand comprises various relationshipsbetween the finger and the string, such as a finger touching the strings, afinger pressing the strings, and a finger releasing the strings. The recognition of the precise fingering of the left hand is applied to aself-learning support system, which is able to detect strings being muted by afinger, and which transcribes music automatically, including the details offingering techniques. Therefore, the goal of our study is the construction of a system forrecognizing the touch of strings for the guitar. We propose a method for recognizing the touch of strings based on theconductive characteristics of strings and frets. We develop a prototype system, and evaluate its effectiveness.Furthermore, we propose an application which utilizes our system.