Arrowheads, needles, hooks and harpoons. Culture: Japan. Dimensions: W. 3/4 in. (1.9 cm); L. 2 1/4 in. (5.7 cm).These implements--an arrowhead, fishhooks, needle, and harpoon--were skillfully carved from bone, a material worked by Japanese artisans since Paleolithic times. They were found in the Obara Shell Mound at Ofunato Bay in Iwate Prefecture. According to information gleaned from shell mounds, or middens, the people of the Jomon period relied on a variety of strategies to obtain food. The large number of fishhooks, fashioned with and without barbs, together with the rich array of marine remains found in these rubbish heaps since very early times indicate that some fifty species of fish and shellfish constituted an essential dietary staple. Toggle-head harpoons, a later innovation, facilitated the hunting of sea mammals. Attaching a line to the toggle allowed the hunter to draw in his prey once the toggle had broken away from the harpoon shaft. Further evidence gathered from thes