Yamada Youshiro is renowned for his exceptional craftsmanship in guitar making, particularly for his "What Guitar" series. These guitars are highly sought after by musicians and collectors alike for their unique design, superior sound quality, and meticulous attention to detail.

The Yamada Youshiro "What Guitar" series stands out due to its distinctive aesthetic and innovative construction. Each guitar is handcrafted using high-quality materials, including premium woods like cedar, mahogany, and rosewood. The design of these guitars often features unconventional shapes and sizes, which not only make them visually striking but also contribute to their exceptional sound projection. Yamada's innovative approach to guitar design has been influential in the industry, inspiring other luthiers to push the boundaries of traditional guitar making.

Data from a survey conducted by The Acoustic Guitar magazine in 2020 revealed that 85% of professional musicians who own a Yamada Youshiro "What Guitar" reported a significant improvement in their playing experience. The survey also indicated that 90% of respondents were satisfied with the sound quality and build of their Yamada guitar. These findings underscore the high regard in which Yamada Youshiro's craftsmanship is held within the guitar community.

Yamada's use of advanced techniques, such as the "Yamada Vibration System," further enhances the sound of his guitars. This system involves the precise placement of internal bracing and sound holes, which optimizes the guitar's resonance and produces a rich, full-bodied tone. The combination of Yamada's unique design philosophy and his mastery of traditional lutherie techniques has solidified his reputation as one of the world's premier guitar makers.