U.S. Marine Lt. Col. Louis Simon, executive officer of the 13th Marine Expeditionary Unit, acts as the commander of troops during the opening ceremony of Exercise Iron Fist 2017, at Marine Corps Base Camp Pendleton, California, Feb. 6, 2017. Iron Fist is an annual, bilateral training exercise where U.S. and Japanese service members train together and share techniques, tactics and procedures to improve their combined operational capabilities. - U.S. Marine Lt. Col. Louis Simon, executive officer of the 13th Marine Expeditionary Unit, acts as the commander of troops during the opening ceremony of Exercise Iron Fist 2017, at Marine Corps Base Camp Pendleton, California, Feb. 6, 2017. Iron Fist is an annual, bilateral training exercise where U.S. and Japanese service members train together and share techniques, tactics and procedures to improve their combined operational capabilities.