"Klotzen, nicht Kleckern! (Boot'em, don't spatter'em!) is one of many famous quotes of Guderian.It shows one example of the Clausewitzian concept of Schwerpunkt (concentrating forces to be strong enough for the decisive battle) in the art of war.
This concept is universally known and somewhat understood (there are misunderstandings!). The real challenge isn't to decide on a Schwerpunkt approach, but to balance between the Schwerpunkt and the other remaining forces.
Clausewitz understood that you need to leave a minimum of forces on duty elsewhere even while amassing forces for a decisive battle. World War battles show this very well; Reserves were sent to the location of offensives, but in fact most forces were left to guard other sections of the front line.
I mentioned Guderian, in part because he provides an interesting example for this challenge in procurement. The infantry of WW2 had great difficulties to advance against defenders on open terrain. The obvious solution was armour support, and thanks to a request/idea by von Manstein this armour support was developed in the form of the early assault gun; a normal tank with a casemate gun and high explosive grenades. Guderian opposed this, fearing for the strength of the armoured divisions; assault guns were competing for funds and production capacities.
Guderian was initially mostly successful, in this internal struggle for resources and the concentration on tanks for the fast troops instead of for infantry divisions is often cited as a superior decision of the Germans in comparison to the French decision to disperse many tanks as infantry support vehicles in 1940.
History didn't end in 1940 and neither did WW2. The actual history went on proving that assault guns were needed (and extremely successful). This was even acknowledged and understood by Guderian, whose armour branch never got enough tanks (but tank divisions were in fact partially equipped with assault guns late in the war) anyway.
The optimisation problem is evident: Back in 1940 the decisive action was the armoured spearhead in the centre an it needed almost all armoured strength. The infantry divisions didn't need to advance much for early operational success. The circumstances were different in 1942-1945 and required a difference balance.
"Klotzen, nicht kleckern!" is a maxim, but maxims must not replace thinking. Maximisation and minimisation are rarely the best idea; we should always strive for optimisation.
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The Western forces of the 60's to 90's had a very important balance problem as well. They had to balance between "line" divisions (equivalent to the vast majority of German WW2 divisions, the infantry divisions) and the mobile operational strike forces (equivalent to the few armoured & motorised German divisions of WW2). Eventually, the former atrophied and the latter formed almost the whole of the Western forces. The operational consequences of having no forces to establish and maintain a somewhat stable line were probably never understood.
The new post-2003 forces of Western nations have partially evolved away from this problem, as even the armoured forces (supposedly "Cold War dinosaurs") atrophied, leaving us mostly with support troops, the traditional establishment of light infantry (mountain, airborne) and some motorised infantry.
We were lucky that the imbalance of the previous generation of forces was never truly tested and exposed in war. Let's hope that we'll be lucky enough to never see the present imbalance tested seriously before we inevitably get rid of it
The Schwerpunkt concept remains valid, but it requires a good balancing in every application. Those other forces that are not focused on the supposedly decisive action are essential and must not be reduced too much.
photo: Bundesarchiv, Bild 101I-139-1112-17 / Knobloch, Ludwig / CC-BY-SA