John Kramer is the real name of the killer known as Jigsaw in the Saw film franchise.
John Kramer is introduced as the mastermind behind elaborate tests that force victims into dangerous choices. He uses the name Jigsaw because he cuts a small, puzzle-piece-shaped piece of skin from certain victims who fail his tests. Tobin Bell played Kramer in the series.
The first Saw film, released in 2004, initially presents the mystery of Jigsaw through clues, recordings, and the experiences of people trapped in a bathroom. Later entries expand his biography and reveal more about his motives, disciples, and methods.
A frequent confusion is that every Jigsaw-related killer is John Kramer. Several other characters carry on or imitate his work, including Mark Hoffman. Kramer remains the original Jigsaw and the central figure whose philosophy drives the franchise's mythology.