Bottom bracket Stronglight JP400 equivalents
From what you say, you need a bottom bracket with:


length = 122mm (as you state)
width = 68mm (you say 69mm, but 68mm is a standard size, could you be 1mm out?)
JIS standard taper (this will make sense to you when you start looking at BBs, the other standard is ISO. In JIS, "J" equals Japan, I suspect in JP400, "JP" also equals Japan)


There's one last variable, unfortunately. This is how the bottom bracket attaches to the frame. It screws in, but there are two different types of thread in common use, English and Italian. The type of threading used depends on the manufacturer of your bike. As a generalisation, Italian threads are (surprisingly) used mostly by Italian makers, the rest of the world pretty much uses English.

So, most likely you'll want an English thread, but you should check this (do you know the manufacturer of the frame?) before buying as the two threads are most definitely not compatible.

NB as always there's a page on Sheldon Brown's website with good information on BBs.