HCESAR (pronounced by saying the name of the letter H and then the word César: in Portuguese, agá-César) is an obsolete typewriter keyboard layout. It was created by decree on July 17, 1937, under Portuguese prime minister António Salazar. The purpose of the layout was to place the most frequently used characters, as they were used in Portuguese, in the center of the layout. It was common that the 0 numeral was omitted (in favour of using the uppercase O letter), and there were also some typewriters without the 1 numeral (with the lowercase L being used to achieve it). Also absent were symbols such as the exclamation mark (achieved by typing an apostrophe and overwriting it with a period using the backspace key), the asterisk (achieved in a similar way, with lowercase X and the plus or minus sign — for eight- or six-pointed asterisks, respectively), the number sign (which was achieved by some through intricate methods involving partial depressions of the backspace key to overwrite the equals sign with two slashes), and the inequality sign (typing an equals sign and overwriting it with one slash). This keyboard layout was the official layout of typewriters in public administration and most private companies until the mid-1970s, when it began to be replaced by the AZERTY layout. When both layouts were in use the HCESAR was called the "teclado nacional" (national keyboard [layout]) and the AZERTY "teclado internacional" (international keyboard [layout]). In the early 1980s, when the Portuguese public administration started to replace its old machines with multiuser terminal-based computers, mainly running the Unix OS, both HCESAR and AZERTY were slowly replaced by the QWERTY layout, which is overwhelmingly used today.