Those who play Go know well that one must learn to adapt to new styles of play and never fall victim to trends or convention. A bannerman for this ideal would be Oda Nobunaga. A brash youth from a moderate family, he quickly rose to power by adapting to the era, new weapons, new tactics, and nearly united his country.
Nobunaga's first real sign came at the Battle of Okehazama. Here, an army estimated at 25,000 men marched on Kyoto, headed by Imagawa Yoshimoto. Nobunaga dared to challenge Imagawa with a tiny force of only 5,000 men. While the forces of Imagawa camped, Nobunuga launched an unexpected attack during a thunderstorm. Many of the Imagawa forces fled without a single weapon drawn. When Yoshimoto left his tent to investigate the commotion, he found a spear in his chest. The lopsided battle had been won by cunning.
source: Samurai Sourcebook : Turnbull
His ingenuity did not stop at matchlocks. Nobunaga was most likely the first to have organized, highly disciplined ashigaru spear units. (The samurai typically fought individually with a spear on horseback. The sword came into prominence at a later time.) Nobunaga also lengthened his spear from a standard 2.5 ken (1 ken=1.6 meters) to 3.5 ken.
Space does not permit a full biography of the Sengoku nor of Nobunaga. His cunning and ingenuity led him to the edge of his dreams. It was here that they fell apart. Readers of Hikaru No Go Manga #6 might remember the small bonus at the end entitled, "Assasination at Honnoji Temple." Of course, the assassination is of Nobunaga himself. Nobunaga had stopped off at Honnoji temple and was surrounded by only a few bodyguards when one of his own generals turned on him and led forces against him. Akechi Mitsuhide was the downfall of every dream and every right turn. Nobunaga was forced to commit seppuku.
Incidentally, a certain Oda Nobunaga watched Honinbo Sansa play Go and with the placing of one brilliant stone Nobunaga was amazed and shouted out, "Meijin!" and thus was born the title.
Turnbull, Stephen Samurai Sourcebook London: Cassell & Co 1998