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.