Flag semaphore is a system for conveying information at a distance by means of visual signals with hand-held flags, rods, disks, paddles, or occasionally bare or gloved hands. Information is encoded by the position of the flags; it is read when the flag is in a fixed position. Semaphores were adopted and widely used (with hand-held flags replacing the mechanical arms of shutter semaphores) in the maritime world in the early 1800s. Semaphore signals were used, for example, at the Battle of Trafalgar. This was the period in which the modern naval semaphore system was invented. This system uses hand-held flags. It is still used during underway replenishment at sea and is acceptable for emergency communication in daylight or, using lighted wands instead of flags, at night.
The following semaphore characters are presented as one would face the signalman:
The flags are specified as a solid white square for the left hand and a solid red one for the right. The display motions chosen are not like the "rotary dial" system used for the Latin alphabet letters and numbers; rather, the displays represent the angles of the brush strokes used in writing in the katakana syllabary and in the order drawn.
For example, the character for "O" [オ], which is drawn first with a horizontal line from left to right, then a vertical one from top to bottom, and finally a slant between the two; follows that form and order of the arm extensions. It is the right arm, holding the red flag, which moves as a pen would, but in mirror image so that the observer sees the pattern normally. As in telegraphy, the katakana syllabary is the one used to write down the messages as they are received.
Also, the Japanese system presents the number 0 by moving flags in a circle, and those from 1 through 14 using a sort of the "rotary dial" system.
In the short story for kids, "The Mystery of the Seven Wrong Clocks" (published in Alfred Hitchcock's Solve-Them-Yourself Mysteries, edited by Robert Arthur, Jr., Random House 1963), a soon-to-be murder victim identifies his murderer using the hands of clocks set in semaphore positions.
The Beatles' album cover Help! (1965), according to photographer Robert Freeman, was originally going to show the Beatles signaling the word HELP in semaphore. However, if read according to the code, George signals an "N" or maybe an "R" or "S", John a "U", Paul a "J", and Ringo a "D", "V", or "Cancel". The images on the US album are out of order, and all of the pictures are mirror-reversed. In the UK order, and reversed, the message appears to spell "LPUS." Freeman has stated that the letters "H-E-L-P" did not look good, graphically. Apparently "LPUS" ("help us") was used as a better-looking substitute (see Freeman, The Beatles: a Private View, p.62).
The peace symbol is a combination of the semaphoric letters N and D, standing for "nuclear disarmament," inside of the European hiway instruction circle.
In the movie "The Last Detail" starring Jack Nicholson and Randy Quaid, Nicholson plays a signalman in the US Navy who teaches semaphore to Quaid while escorting him to military prison. Quaid signals: "Bravo Yankee, Bravo Yankee, end of message" before attempting an escape.
In Arthur, the Brain has a dream where his strict teacher makes the class take a test in semaphore.
In the Simpsons Admiral Nelson sends a message to Captain Skinner which reads "Skinner eat fly dolphin booger."