R. Kahaneman was on a mission abroad when World War II broke out. In 1940 he settled in Erez Israel and from there directed efforts, in vain, toward the rescue of Lithuanian Jewry from the Nazis. Most of his family perished in the Holocaust. Thereafter, he devoted himself to reestablishing in Erez Israel a network of Torah institutions. In 1943 he established Batei Avot, an orphanage for refugee children. At the end of 1944 he laid the foundation of the Ponevezh Yeshiva in Bnei Berak with seven students. Over the years, he traveled throughout the Jewish world to enlist financial support for his ambitious venture. The result was Kiryat Ponevezh, where more than 1,000 students have studied and which has included hostels for children and adults, a large library, and a memorial to Lithuanian Jewry. He instituted the yarhei kallah, an annual summer refresher course in talmudic studies for adults. All this, he stated, he did "with 21 fingers," those of his hands and feet and the finger of G-d. In later years, he established a branch yeshivah in the development town of Ashdod. He was widely revered among all sections of the population. The Ponevezh Yeshivah in Bene Berak and its sister institution in Ashdod have thrived along with the communities R. Kahaneman built around them. In 1989 and again in 2003, collections of Kahaneman's writings and lectures were published, Kovez Shi'urim ve-Hidushei Torah and Sefer Divrei ha-Rav, respectively.