Determining the "greatest" samurai is subjective and can vary depending on personal opinions, historical context, and criteria used for evaluation. Throughout history, there have been numerous samurai who achieved great feats, displayed exceptional skill, or left a lasting impact. Here are a few notable samurai who are often regarded as some of the greatest:

1. Miyamoto Musashi: A legendary swordsman and strategist of the 17th century, Musashi is known for his exceptional skill in duels and his writings on martial arts and philosophy, particularly "The Book of Five Rings."
2. Takeda Shingen: A powerful daimyo (feudal lord) during the Sengoku period, Takeda Shingen was renowned for his military tactics, leadership, and strategic brilliance. He was a key figure in the conflicts of the time.
3. Date Masamune: A prominent daimyo of the late 16th and early 17th centuries, Date Masamune was known for his skill in battle, his diplomatic abilities, and his patronage of culture and the arts.
4. Honda Tadakatsu: A loyal retainer of Tokugawa Ieyasu, Honda Tadakatsu was a highly skilled and feared warrior known for his remarkable strength, proficiency in combat, and impressive armor.
5. Minamoto Yoshitsune: A famous samurai of the late 12th century, Yoshitsune is celebrated for his military leadership, bravery, and tactical prowess during the Genpei War.

These are just a few examples, and there are many other renowned samurai throughout history who have made significant contributions. Each samurai's greatness is often assessed based on their individual achievements, military prowess, leadership skills, cultural impact, and the historical context in which they operated.