On Saturday, January 25, I attended an in-service conducted by Jim Rosebrock (Antietam Guide Service) about interpreting a battlefield the way the military does today. I found it enlightening and very practical and believe I need to share it with others. Very often, when visitors come to Antietam, they do so with a vague idea of what happened there. They see the excellent video. They take the self-guided tour, visit the bookstore, and often hire a guide to take them on a 2.5-hour tour of the field.
While visiting the undulating Cornfield, the Bloody Lane and the iconic Burnside Bridge they often ask “Why?” Why did the men fight in shoulder-to-shoulder battle lines? Why did they get so close to each other before opening fire? Why would they attack over such open ground? Why did they stand up to fight, rather than lie down?
To understand the “why,” a person has to know the “how.” That is where Jim’s presentation comes in. The military acronym for interpreting a field is OCOKA: Observation and Fields of Fire, Cover and Concealment, Obstacles, Key Terrain, and Avenues of Approach.
a. What can you see from where you are standing?
b. Are there hills, woods obstructing your view?
c. Is there smoke or ground fog blanketing the area?
d. Is it raining, snowing, or, worse yet, lightning and torrential rain?
e. Are you on the best ground from which to observe the field?
f. Is there a town blocking the line of sight?
2. Fields of Fire
a. Where do you place your artillery to be most effective?
b. How close do you have to get to see the enemy?
c. How does the terrain affect your placement of troops?
d. How do you establish your line to get the clearest line of fire?
a. What landscape features and or manmade structured will provide your soldiers from incoming fire?
b. Stonewalls, rock ledges, wooden fences, and buildings along with depressions in the ground can protect troops from direct fire but not necessarily from plunging fire like shell and case shot bursts.
i. Sunken roads and depressions are subject to enfilade, defilade, and flank fire
ii. Stonewalls can produce collateral damage from direct hits from artillery projectiles and incoming small arms fire.
iii. Rail and board fences are subject to splintering and do not provide solid cover from incoming fire.
c. Cover is preferable to being out in the open. Proper use of it might not eliminate casualties but can perhaps reduce the number of them.
a. Concealment means that the troops are protected from observation and not necessarily from fire, though cover and concealment may occur at the same time.
b. Troops use concealment to mask their movement upon an enemy position.
i. Woods, creek beds, swales, ravines, and sunken roads may remove troops from enemy observation.
a. What on the field can impede your approach onto the field and how are they classified?
i. Go – dry ground, not a lot of man-made obstacles, concealed approaches, anything that facilitates rapid, hidden movement.
ii. Slow Go – hills, fences, overgrown woodlots, bad roads, plowed fields, ground hog holes (Antietam), streams, creeks, fog, low visibility, snow, rain, all of which reduce quick deployment.
iii. No Go – torrential rain, blizzard conditions, mud, swamps, deep water, cliffs can bring any advance to an abrupt halt.
6. Key Terrain –
a. Elevations, which can be used for observation.
b. Choke points which make it difficult for the enemy to escape.
c. Any location, which, if occupied and held, will effectively guarantee the success of the mission.
7. Avenues of Approach
a. Terrain, which will facilitate rapid and successful approaches to the objective.
When visiting a battlefield apply OCOKA to the ground around you. It might explain, in part, how the battle was fought.