IS1 - M3 Sakura Real-Time Save 1 File
This is a data file created by the M3 Sakura loader for the Nintendo DS. It runs on the M3i Zero and M3DS Real flashcart. These files are used to enable storing of the game state while the game is being played. It is also used to save game snapshots even at points where the game itself doesn't allow snapshots to be taken. Along with the IS1 file extension, M3 Sakura also uses additional numeric extensions such as IS0, IS2, IS3, etc. to save additional copies of the game state and snapshots.
Due to the cessation of support for the M3 Sakura flashcarts, most Nintendo DS ROMs produced after March 2011 will not work with them. Also, the M3 Sakura systems do not work with the Nintendo 3DS. The last known data file for the M3i Zero is dated 01/06/2012 and is version 4.1.0. The last known revision for the M3 Sakura is v1.49x 3rd edition (M31) and for the Touchpad is v4.9aX (M71). These revisions are dated 02/18/2011.
While one of the best flashcarts available at the time, since support has ceased, these flashcarts are no longer viable products and other alternatives are available.