From MangaHelpers:

This historical manga takes place in the Tensho period, near the end of Japan's long Warring States Period, at the point where the gradual unification of the country was in progress. The story features an interesting character in history, Sengoku "Gonbei" Hidehisa. Hidehisa began as a low ranking samurai, but he grew into prominence. He made a number of disastrous mistakes in his life, but he somehow managed to not only survive them, but to also regain his status. This manga reveals the mystery of Hidehisa's intriguing life, as the Warring States Period draws towards its close!

Note: This appears to be part of a series of manga about Hidehisa's life. The first is "Sengoku" (which begins in 1567), the second is "Sengoku Tensho-ki", and this series presumably carries on where the second left off. There is also a series that seems to be a prequel: Sengoku Gaiden: Okehazama Senki.