Super Mario 64 · Nintendo 64 · Skip · Saves: Enables the 0-star and 1-star categories (skips roughly 70 stars of content) · Documented: 2004
A speed accumulation glitch in which repeated backwards long-jumps on narrow staircases build velocity past the game's signed 16-bit speed cap, causing the value to overflow negative and teleport Mario through star-locked doors.
The backwards long jump is the technique that defines Super Mario 64 competitive speedrunning. Mario's speed in the game is stored as a signed 16-bit integer. Long-jumping while walking backwards accumulates a negative velocity that, when added to itself repeatedly on an inclined surface with collision occurring each frame, grows rapidly. Once the value exceeds the negative range of a 16-bit signed integer, it wraps around to a very large positive number — a classic integer overflow. This extreme positive speed is applied for a single frame as a forward burst, passing Mario through the collision geometry of star-locked doors and barriers that would normally require him to have collected a specific number of Power Stars to open. The BLJ enabled the 0-star category, in which a runner reaches and defeats Bowser in the Final Battle without collecting a single Power Star, turning a game designed around 120 stars into a roughly seven-minute run. It also unlocked the 1-star category and shaped the entire Any% route around the fastest path to the first BLJ-accessible staircase.
Super Mario 64 represents Mario's forward speed as a signed 16-bit value, which can hold integers from −32,768 to +32,767. Long-jumping while moving backwards applies a negative speed value each frame. On a staircase where ground collision is triggered every frame, each collision adds another increment of negative speed rather than resetting it. Within roughly fifteen to twenty repeated jumps the accumulating negative value crosses the −32,768 boundary and overflows, wrapping to the maximum positive value of +32,767 or thereabouts — a velocity that moves Mario dozens of in-game units per frame, far beyond any speed achievable through normal play.
This burst of positive velocity is what passes Mario through locked doors. The game's collision for star-locked barriers checks whether Mario's star count is sufficient before processing movement for a given frame. The BLJ's overflow frame moves Mario so far that he is placed on the other side of the barrier before the next collision check runs, bypassing the star requirement entirely.
Before the BLJ was discovered and understood, any% Super Mario 64 runs required collecting enough stars to open the game's major progression gates: 8 stars for the Bowser 1 door, 30 for the second key door, and 70 for the Endless Stairs. The BLJ rendered those requirements irrelevant. Runners found they could BLJ through the 8-star door at Bowser in the Dark World without collecting any stars at all, then BLJ through the Endless Stairs to reach the final Bowser immediately after. The theoretical star count needed for a complete run collapsed to zero.
The 0-star category became one of the most watched speedruns in online streaming history, partly because the contrast between the game's designed scope — 120 stars across fifteen worlds — and what runners actually visit (approximately three rooms) is so startling. The BLJ is the linchpin of that contrast, and it remains the most iconic technique in the N64 speedrunning catalogue despite being patched out of every modern port of the game.