Rank insignia plaque

"You are in command now, Admiral Piett."

- Darth Vader, promoting Captain Piett

Rank insignia plaques, also referred to as rank pins, were badges used in the military forces of Sheev Palpatine's Galactic Empire as a means to indicate and distinguish officer ranks. They were originally used by Republic officers during the Clone Wars, when Palpatine was still Chancellor of the Galactic Republic. The plaque, which was worn on the left side of the regulation tunic over the heart, consisted of translucent, colored rectangular tiles mounted on a metal bar. Those plaques could comprise one or two rows of tiles mounted on top of another. Double-row plaques were made from two separate parts of one row each, rather than two rows of caps on a single backing piece. The different types of tiles came in blue, red, yellow, grey, and green. Members of media organizations such as the Imperial Press Corps wore Imperial media badges.

Galactic Republic insignia
As exemplified by Wullf Yularen, Kilian, and Coburn, a fleet admiral wore an insignia that bore three red tiles on the top bar, and two blue tiles on the bottom bar. Many clone navigation officers, some of whom held the rank of captain, wore a single-rowed plaque, with two red and one blue tiles (from left to right).

Galactic Empire insignia
Two red tiles over two blue was the badge of a lieutenant. The rank of Captain, Commandant was signified by three red tiles over three blue.

Members of the Imperial Security Bureau, such as Agent Kallus, wore plaques with three blue squares next to two yellow ones or plaques with two red squares next to one silver and one blue.

As a Vice Admiral, Rae Sloane wore a plaque that featured five red squares over five blue ones. An Admiral's plaque was made of twelve multicolored squares, six red over six blue.

The rank pin of a Grand Moff also bore twelve squares&mdash;six blue over trios of red and gold. A Moff had ten squares; five blue over three red and two gold. The plaque of Grand Generals and Grand Admirals had twelve squares, three blue and three gold over trios of blue and red.

The badge of a junior lieutenant had two red squares sitting on top of two blue.

Imperial rank insignia could be encoded with information readable by devices such as electronic locks.

Behind the scenes
According to Pablo Hidalgo, the rank badges "only mean anything in Empire Strikes Back". In A New Hope, all the plaques (except Grand Moff Tarkin's) look different than in the rest of the trilogy; in Return of the Jedi, all of the plaques were mistakenly made as commander plaques due to a costuming error, even those of Admiral Firmus Piett and Moff Tiaan Jerjerrod. The movie Rogue One: A Star Wars Story features both styles of plaques, and Hidalgo hinted that there is an in-universe explanation.