Discovered by: Several people
The 5bj is one of the few surviving advanced bomb techniques from the original Metroid Prime that is present in Echoes. It was born initially out of the search for a way to complete the Geothermal room in Metroid Prime without Space Jump. The bomb jump works by using the physics of the Metroid Prime games to "build momentum" with additional bomb explosions.
The best way to describe a 5bj is its a double bomb jump with an extra bomb and different timing to place the second bomb. Here is how its done:
Place the first bomb on the ground.
The instant the first bomb goes off place the second bomb.
Near the height of your jump place the third, then fouth bombs.
Near the height of your jump place the fifth bomb.
You will then fall down as the second bomb goes off, sending you up into the third then fourth bombs as they go off. Basically it makes it into a dbj only you have 2 bombs in the air instead of one. So you get a little bit of an extra push.
Also, like most bomb jumps, the 4bj can be done as a Morphed Bomb Jump and/or a Laddered Bomb Jump.
A variation of the 5bj is the TRHbj which involves different timing for placing the bombs.
A video demonstration of a Morphed 5bj followed by a morphed TRHbj (http://trh.metroid2002.com/vids/echoes/2tbj_tbj_comparison.avi)