At the time, most intelligence officers had little motivation and collected meager information about the enemy directly in front of them. Koch handled things differently. He took in everything he could get. He knew troop positions, towns, rivers, railways, bridges, contours, and every other little thing for hundreds of miles around.
His collection methods were as varied as the data coming in. Reconnaissance planes would mark enemy positions. Draftsmen would map out an entire area to determine optimal paths around obstacles. American soldiers that could pass for Germans would disguise themselves behind enemy lines and eavesdrop in bars and restaurants. Encrypted radio transmissions would be broken.
All of this data would pour in for analysis by Koch. In Patton's war room, he would physically mark everything he could onto a large 1:250,000 scale map showing the entire Western Front.
That's great and all, but what's really impressive is how Koch was able to tie together subtle troop movements, on both sides, and realize that a large counteroffensive was imminent.
Around October of 1944, Koch noticed a buildup of German troops to the north. At the time, most intelligence officers considered the area of the Ardennes Forest to be a rest area for the Germans, where troops rotated in and out between stints. Movement was not uncommon. However, Koch felt something was unusual. Wehrmacht troops were collecting there in much higher numbers. More of the movements occurred at night. All of the movements were under complete radio silence. The Germans clearly did not want the Allies to know about this.
Koch reported his ideas to Patton in very certain terms. Considering Koch's reluctance to speak in certainties unless, well, absolutely certain, Patton took him at his word and established a contingency plan to shoot north if anything should occur. Regrettably, most intelligence officers did not agree and assumed the German army was too weak for such a counteroffensive.
As Patton made his march eastward, Koch received signal intelligence of the Germans leaving their staging area before switching to radio silence. Koch reported that the Germans were almost certainly launching their attack. Patton immediately turned his army 90 degrees to the north and flanked the Germans during their attack.
Even though the Germans did break through the Allied line, they eventually ground to a halt and Patton's army rammed into their southern side while Field Marshal Bernard Montgomery pinched from the north. Supply lines were cut and the German troops eventually had to retreat.
The important thing to take away is this: thanks to Koch's thorough intelligence, Patton's army was ready and able to counter the German offensive before it even had a chance to start. I just thought that was very impressive.
Sources:
"Killing Patton" - Bill O'Reilly, Martin Dugard
"Oscar Koch and the Confidence of the Commander"
"Oscar Koch: An Unsung Hero Behind Patton's Victories" - MAJ Kevin Dougherty (p.66-68)
