Kesawo's successor, his grandfather Kunio, shifted the business to electric guitar painting when electric guitar production became popular in Matsumoto City. "Lacquerware involves manufacturing and sales, so if you're not good at selling, you can't sell. But if you only focus on selling and can't produce the products, you can't sell them either. So, I think he wanted to cut out the 'selling' process completely to streamline operations." Grandfather Kunio took on the challenge of significantly changing both the business content and its structure, without altering the core principle of 'painting wood.' Then, his father, Masataka, created 'Matsumoto Keisei-nuri,' utilizing guitar painting techniques. This was an innovative approach that applied guitar painting techniques to lacquerware products such as trays and boxes. The series incorporating autumn leaves collected from the mountains of Shinshu also obtained a patent. Most lacquerware features shades of black, red, and gold. When colorful products are placed among them, they naturally catch the eye. "They sold very well as gifts, with a modern feel." In this way, they once again challenged the 'selling' process, which they had once let go of, with new products. However, it was temporarily suspended from sale as it could not be reconciled with electric guitar production.

Santai has consistently engaged in 'wood painting' since its founding. However, it is said that even though it's the same painting, the content is completely different for lacquerware and guitars. "My grandfather apparently had a lot of trouble when he switched from lacquerware to guitars. The paints, painting methods, and tools were all different, so he had to completely change the equipment." Furthermore, the approach to painting differs between lacquerware and guitars. Guitars require a thicker coat of paint for protection and to correct wood shrinkage and warping. "For electric guitar painting, it's better to apply as thin a coat as possible for sound quality. It seems contradictory, but maintaining a balance between protection and sound quality is one of the techniques of guitar painting." Moreover, compared to general lacquerware, guitars have complex shapes to meet the diverse demands of users, which also presents a challenge.

Color-related issues are common in guitar painting. "For example, a white with a bluish tint and a black with a reddish tint are completely different in shade. When customers order, they might just say 'white' or 'red,' but if it doesn't match the 'white' or 'red' they envision, it can lead to problems." However, such problems rarely occur at Santai. This is because they conduct thorough interviews and materialize the image in the customer's mind. Furthermore, they sometimes inform customers in advance about potential issues with an order and propose alternatives. "We have pride as craftsmen in our work. However, I think it's uncool to force what we want to create on customers under the guise of 'craftsman's spirit.'" For this reason, they take the stance of listening carefully to customers and providing what they desire, such as specific color preferences and delivery times. Santai is likely supported by customers because it combines the skills of a craftsman with the spirit of a service industry. "Our ability to respond to customer orders is also because we have many 'drawers' (solutions/options) to meet any request."