A Phase III study was started in Japan to evaluate the non-inferiority of overall survival of laparoscopy-assisted distal gastrectomy with open distal gastrectomy in patients with clinical IA (T1N0) or IB T1N1 or T2(MP)N0 gastric cancer. This study followed the previous Phase II study to confirm the safety of laparoscopy-assisted distal gastrectomy (JCOG0703) and began in March 2010. A total of 920 patients will be accrued from 33 institutions within 5 years. The primary endpoint is overall survival. The secondary endpoints are relapse-free survival, proportion of laparoscopy-assisted distal gastrectomy completion, proportion of conversion to open surgery, adverse events, short-term clinical outcomes, postoperative quality of life. Only a credentialed surgeon can be responsible for both open distal gastrectomy and laparoscopy-assisted distal gastrectomy.