It's not actually a dress hat, but standard issue for field use for many nations. It's pinned up on the left side to allow a soldier to march with their rifle slung. It's typically Australian/ANZAC since we've used them since the Victorian era, and it stuck in people's minds since they look damn good for a field hat, especially with the gold rising sun pin. It can be unpinned to shade your ear. The standard for kiwis was to wear the hat flat-brimmed, and only pin it up during extended marches. Australian armed forces have a pinned slouch hat as part of the formal dress uniform, and the two are differentiated by Grade 1 (dress) and Grade 2 (field) slouch hats. Grade 1 hats are much more elaborate and feature unit insignia/colours and will be worn/styled differently depending on unit tradition.
Interestingly, even the Germans were known to wear slouch hats in areas like Africa and south-east Asia during WWII, except they wore theirs pinned up on the right side with a silver-grey imperial eagle.
"Oh, they'll never hit us from all the way over th-"
Last edited by Khargoth; 06-25-12 at 05:57 AM.