Trench warfare
Trench warfare occurred when a revolution in firepower was not matched by similar advances in mobility, resulting in a grueling form of warfare in which the defender held the advantage. On the Western Front in 1914–1918, both sides constructed elaborate trench, underground, and dugout systems opposing each other along a front, protected from assault by barbed wire, mines, camouflaged trapping pits, and other obstacles. The area between opposing trench lines (known as "no man's land") was fully exposed to artillery fire from both sides. Attacks, even if successful, often sustained severe casualties.
32nd Infantry Division (United States)
Captain Alien L. Briggs returned to Camp MacArthur to assist with training. He had been an Aide-de-camp to General Parker and had been in Europe when the war broke out in 1914. He had observed the training methods used in military schools in France. As training intensified in preparation for leaving for France, five French and four British officers, along with several non-commissioned officers, joined the division as instructors. A trench system was built outside the camp in which the division practiced the techniques of trench warfare. There was a continual shortage of equipment that hampered training in the artillery and machine gun battalions. Additional training for junior and non-commissioned officers was implemented, and General Haan offered additional daily instruction to the brigade, regimental and battalion commanders.