Adjuvant chemotherapy is aimed at eradicating residual micro-metastatic tumor cells existing at the distant site outside of the surgical field. From evidence gathered from around the world, several courses of intensive neoadjuvant chemotherapy are promising even in Japan, where D2 surgery is the standard for local control. The Japan Clinical Oncology Group (JCOG) plays a central role in the development of neoadjuvant chemotherapy in Japan. Two JCOG Phase II trials clarified that neoadjuvant chemotherapy was effective for bulky nodal disease. A JCOG Phase III is now on-going to confirm the efficacy of neoadjuvant chemotherapy of S-1+CDDP for cancer of the schirrhous type. In another group, two randomized Phase II trials are also ongoing to compare different regimens and courses of neoadjuvant chemotherapy. These studies will set the direction of neoadjuvant chemotherapy development in the future.