A checkpoint, first introduced as a lamppost in Sonic 1, will save the player's progress throughout a level. The player can restart from an activated checkpoint if they die. Checkpoints also serve as the entrance to a special stage in Sonic 2 and the entrance to a bonus stage in Sonic 3 and Sonic & Knuckles.
The lamppost design from Sonic 1 is also used in Sonic CD, albeit with a smoother animation cycle upon interaction.
In the 8-bit version of Sonic 1, monitors are used instead of lampposts. Destroying the monitor has the same effect as touching a lamp post; however, the current time is not recorded and you start with 1:30 minutes after your death. Checkpoints aren't present in Sonic 2 nor in Sonic Chaos. Sonic Blast used the same system, the only difference being that the pictured arrow is red as opposed to yellow.
These two games' checkpoints look quite similar to Sonic 1's lampposts, except that the bulb is replaced by a star disc and the pole design is slightly different. When Sonic runs past the star post, the disc starts flashing and (if the player has enough rings) revolving stars appear which enable access to a special stage or bonus stage.
In Sonic 3 & Knuckles, three different types of bonus stages can be entered. The bonus stage offered by a given star post is indicated by the color of the stars:
The next game in the Classic series, Sonic 4 also uses this version of the checkpoint without the revolving stars.
Future 3D games games use a redesigned versions of the 16-bit version Sonic 1 lamppost; in these games, two double-lampposts, called a Point Marker, are bent at 90-degree angles, with their blue tops facing each other. Running through the Point Marker causes these tops to spin quickly, turn yellow, and bend to a standing straight-up position. Later 3D games use other versions of markers as well, like in Sonic Heroes where the markers give players a level-up.