Found this on the net.
[History of the Grand Concert Custom sound]
Basic form of what today is known as the classical guitar is in the 19 century Spain guitar production house Antonio de Torres （ ANTONIO DE TORRES:1817-1892 ） by was made.
Its style and technology handed to Spain affected his production house were, and then from Spain spread to the world.
4/1966, Yamaha will establish a guitar Research Division, started research and development of handcrafted guitars.
From October the same year next day ' craftsman tradition of Torres 67, Spain Eduardo Ferrer greeted us (Hamamatsu), Spain tradition of technology leadership.
By the hands of the craftsmen who learned this when ' was born in the 11/67 Grand Concert Guitar early model GC-5, GC-7, GC-10. This 3 model based on the orthodox sect Spain style gave great influence after Japan-made guitars.
It is this later as Spain Orthodox traditional manufacturing methods based on repeated trial manufacture and study, we had grabbed gradually sound relations, relationship between production processes and sound materials and structures and.
In 1972, Yamaha sent an engineer who in Spain.
He studied ethnic guitar craftsmen Eduardo Ferrer and Manuel Hernández, learned the production techniques over two and a half years in the culture of the home.
In addition ' in 1973, Hernandez, held technical leadership in Hamamatsu.
And sounds make this a new origin, we asked different types of tone, continued research and development. And guitars in 1974, custom guitars GC-a 30/30 / 30 C 3 type a personalities are announced.
GC-30A is a model combining methods learned Hernandez as the culmination of technologies accumulated in the GC series until it was developed as a premier Yamaha original sound.
GC-30B's model Hernandez manufacturing methods and ways of thinking, and pursued the sounds of Spain.
GC-30C is a model developed to help Spain craftsman soundboard sound, feel attracted to the sound of guitar time has elapsed.
These 3 types of sounds is further research and improvement, and has been handed down to was released in 1983, GC-50/60/70, GC-61, GC-62.
Also acclaimed musician prominent in the same 1983, Andres Segovia model GC-71 has been released.