Japan Tune-up In the Series (Japan Tune-Up Series), commonly known as the “JT Series”, each instrument is meticulously adjusted one by one at the Deviser Technical Center in Matsumoto City, Nagano Prefecture, with no effort spared, resulting in a level of fine-tuning that allows professional guitarists to take the stage immediately. The manufacturing process focuses primarily on the fundamental steps involved in crafting guitars, which is why the skills of each individual craftsman are so important. By incorporating techniques from the Aska Workshop, where our craftsmen are responsible for manufacturing domestic products for our group companies, we are able to achieve the same high level of finish and cost-performance as our domestic products.