There is no such thing as Zen Buddhism. Zen is a religious philosophy and a way of meditation mainly practiced by Buddhist monks and artists. By practicing Zen, monks wrote many books and artists produced a variety of arts, including Shodo, Chado and Kado that are still alive today as traditional culture of Japan.
On the other hand, samurai were warriors (military); they were not interested in religious practice. Samurai studied Confucianism and Bushido as their code of conduct which emphasizes
You don't need to understand this Japanese. But my point is that Zen, as a religious philosophy and a way of meditation, did not have much impact on Samurai and Daimyo class, but Confucianism and Bushido did.