Born in 1544 as the son of Takenaka Shigemoto, lord of Omido Castle in Mino Province. His given name was Takenaka Shigeharu. In 1564 he performed the astonishing feat of seizing the formidable Inabayama Castle with only 16 men to remonstrate with his incompetent lord Saito Tatsuoki — entering the castle on the pretext of visiting his brother, he took it from within. Yet he returned the castle to Tatsuoki half a year later and retired into seclusion. After the Saito fell to Oda Nobunaga in 1567, Shigeharu became a ronin until around 1570, when he joined Kinoshita Hideyoshi (later Toyotomi Hideyoshi) as a military advisor. Thereafter he displayed brilliant strategy in battle after battle, and together with Kuroda Kanbei (Yoshitaka) was celebrated as one of Hideyoshi's 'Two Great Strategists' (Ryohyoe). When Araki Murashige rebelled and Nobunaga ordered the execution of Kanbei's young son Shojumaru, Hanbei secretly sheltered the boy and saved his life. In 1579, while serving in Hideyoshi's campaign against the Mori in western Japan, he fell ill with tuberculosis during the siege of Miki Castle and died in camp at the age of 36. Though he died young, his genius became the stuff of legend.

Calm, composed, and free of greed. Though frail in body, he excelled in strategy and preferred winning without fighting. Remarkably disinterested in power — he seized Inabayama Castle yet returned it without claiming it for himself.

Counted alongside Kuroda Kanbei as one of Hideyoshi's 'Two Great Strategists' and ranked among the foremost military advisors of the Sengoku era. The tale of seizing Inabayama Castle with 16 men endures as one of the period's greatest feats of cunning.