Yissaschar was born in Warsaw on Yom Kippur, October 7,1927, to Avraham and Sarah. In 1932 the family made aliya  settling in Tel Aviv. From his parents he absorbed the awakened spirit of Israel preparing to liberate its land, and in school the heroic stories of the wars of the people of Israel shaped  his being.  A considerable athlete, he was active in the Scouts and  Maccabi sports, mostly instructing. He planned studying to become a professional sports teacher, so as to mould  a healthy new generation.  He completed a year of national service 1943, at Ramat-Hakovesh, where he underwent his first military training; a year later he got a job as  driver in the British Army, enabling him to learn to interact with the British, learn their ways, their security methods in military bases, and observe their convoys. All this proved highly  useful later for the underground, which had at the time already intensified its war for  Liberation of the Land. Yissaschar, captivated by Lehi’s spirit, joined under code-name  Ya’acov (Yanka’le). Placed in  the Combat Brigade he partook  in much combat, dedicated entirely, with youthful fervor, to combating the foreign occupiers. It was he who, with his good friend Jimmy, exploded a bomb at the heart of British forces in Sarona (today IDF Headquarters Tel Aviv). In 1948 he participated in the Lehi activities against the British and Arabs in Jerusalem and in Lehi’s battles in the neighborhoods of Romema, Lifta, Sheikh-Bader and Deir-Yassin. Wounded in one of the attacks, he nevertheless returned to the battlefield before recovering. His daring and courage were  reputed. On the day the British evacuated Jerusalem, he was among the first fighters charging ahead to take over British security-compound buildings (dubbed ‘Bevingrad’), and onwards to the fighting at the Wall. The following day, May 15,1948, an enemy bullet mortally wounded him while climbing to the  ‘Death Roof’ of  battle-scarred ‘Notre-Dame’ building.  Yissaschar was buried in the Military Cemetery atop Mount Herzl, Jerusalem. Shortly afterwards, Leah Prisant, his Lehi betrothed, was killed.