The free, semi-nomadic life of the Jomon was disrupted around the time of Aristotle by the arrival of various groups of invaders known collectively as the "Yayoi." These Bronze Age warriors eventually replaced the Jomon, first driving them farther into the north and finally eradicating them entirely. The gods and culture of the Yayoi indicate a tropical origin, perhaps the vicinity of South China. They settled in the southern islands, where they erected tropical dwellings and began the cultivation of rice. Soon they were making implements of iron, weaving cloth, and molding pottery using the wheel and high- temperature kilns. The descendants of the Yayoi became the Japanese people. For the first several hundred years of Yayoi hegemony, their ceramics, although technically more sophisticated, showed less artistic imagination than those of the Jomon. In the fourth century A.D., however, after the consolidation of their lands into a unified state, a new era of artistic production began. From this time until the introduction of Buddhism in the sixth century, an interlude known as the Mound Tomb era, the arts of Japan blossomed, producing some of the finest sculpture in the ancient world. The Yayoi mound tombs, often many acres in size, were filled with the implements of their aristocratic owners (much as were the pyramid tombs of Egyptian pharaohs), and around their perimeters were positioned hollow clay statues, presumably as symbolic guardians. These realistic figures, ordinarily two or three feet in height, are today known as _haniwa_. Fashioned in soft brown clay, they portrayed virtually all the participants in early Japanese life: warriors in armor, horses standing at the ready, courtiers, rowdy farmers, fashionable laThes-in-waiting, and even wild boar. The making of _haniwa_ died out after the sixth century, as Chinese Buddhist culture gradually took hold among the Japanese aristocracy, but the underlying aesthetic values were too fundamental to perish. When Zen culture came to flower in medieval times, all the early artistic values awoke from what seems to have been only a slumber; monk-artisans returned to an emphasis on natural materials--whether in soft clay tea bowls, in unworked garden rocks, in the architecture of unfinished woods, or in a general taste for unadorned simplicity. These men created their art and architecture from seemingly rough and imperfect materials out of deliberate choice rather than necessity--a preference rare if not unique in human experience.