FORT HOOD, Texas -- The California Army National Guard's 40th Infantry Division Headquarters Forward will soon deploy overseas for the first time since the Korean War.

The 40th ID Headquarters Forward will replace the Texas Army National Guard's 36th Infantry Division as a division command element in Train Advise Assist Command South in Afghanistan. Having National Guard units fulfill this mission is part of the Army Total Force Policy that requires all Reserve and National Guard units to meet the same readiness standards as their active-duty components and be capable of the same missions.

"It's a big deal, it's a great opportunity for the California Guard to shine," said Brig. Gen. John Lathrop, Commanding General of 40th ID Forward.

First Army Division West has been partnering with the unit to ensure the California Soldiers are ready and trained for their historic mission to southern Afghanistan, and the 40th ID Headquarters Forward concluded a five-day Mission Rehearsal Exercise at Fort Hood Sept. 30.

"Our biggest challenge is making the exercise relevant to what they'll see in theater," said Army Reserve Lt. Col. Mario Villegas, an exercise project officer from the 75th Training Command. "We take a year's worth of knowledge and condense it into five days."

Soldiers from the 4th ID, 24th ID, 25th ID, III Corps, 101st Airborne Division, and Airmen from the 5th and 116th Air Support Operations Squadron also participated in the exercise.

"I think this exercise demonstrates 16 years of deployments," said Col. Peter Cross, the chief of staff for 40th ID Forward, who deployed to Operation Desert Shield/Storm in 1990, and Operation Iraqi Freedom in 2005 and 2009. "This process has been refined so there's very little effort wasted."

First Army's Lt. Col. Will Laase, commander of the 2-393rd Brigade Support Battalion, 120th Infantry Brigade, explained the MRX as a series of "vignettes" -- scenarios fed to the 40th ID headquarters that required a timely and effective reaction.

"The vignettes stimulate the staff to plan, and the commander to make a decision," Laase said.

Though this training exercise lasted five days, it was just the final event in more than 18 months of training and preparation. One of the first, and arguably most important, steps in this process was for Lathrop to establish the commander's training objectives: the conditions and doctrine the 40th ID staff needed to meet to be ready for the mission.

"First Army has been there every step of the way, teaching, guiding, coaching and mentoring," Lathrop said. "The 40th ID is a learning organization. I believe having that outside look in enables us to do that."

The mobilization to TAAC-S is divided into four "turns." The first two turns are the previous and current 36th ID Soldiers deployed to TAAC-S. The current 40th ID Headquarters Forward about to depart for TAAC-S to relieve the 36th ID are Turn 3. 40th ID Soldiers who will assume the mission a year from now are designated as Turn 4.

"This exercise would not be possible to this degree of success without the 36th ID. This is a three-way partnership," said Maj. Gen. Todd McCaffrey, commanding general of First Army Division East. "First Army feels very strongly about this -- the 40th ID's success is our success."