The stimulus that prompted the development of aviation was the early attempt to break the aviation record, and war, as well. In the first world war, pocket watches and new watches evolved into the early pilot watches. British Mark IV A and Mark V pocket watch were the first watch that were applied to the battle. The first world war reminds of the combat plane with a propeller and machine guns that were used on the air combat. Romantic aviation spirit is added to the combat romantic spirit, satisfying the need for precise navigation. So the importance of a pocket watch was highly emphasized.

The case Back with information about countries, institutions, featured the old military watch. The Great Britain mark is a broad arrow. For collectors, the information on the case back is crucial and is the guarantee. Those marks mean they were the standard issue for a soldier, and were purchased for pilots through contract. On 13^th, April, 1912, British RFC was basically founded, as a military unit of navy. Considering the unique demand from fleet, navy cut off its connection with RFC, and then it evolved into RNAS. In 1918, there two independent branches once again constituted RAF, and continued use those old Mark pocket watches. This series RFC pocket watches has a big letter A that was underlined. A repaired pocket watch means an extra case back that could not be recovered. Mark IV A shares the same standard with Mark V. RFC and RNAS almost has the same pocket watches, but RNAS has 8 days of energy reserve while RFC only has 30 hours. `Once they get into cockpit, they are the same, namely, the chronograph tool.

Mark series has various editions. For example, the luminous edition is required for the night flight as it could offers clear reading for pilots, monitor fuel consumption and navigation in the dark. The Mark V, with 8 days of energy reserve, is good for long flight. Flight requires fuel up on it, and as the tool for pilots, its purposes are settled. No a environment is harsher than the real battle. The war gave birth to the large produce of it. War is a serious thing, and its existence is the evident of human’s failure, but war is inevitable sometimes, and the urgency from war pushed watch producers produce more of watches, including some replica luxury watches.