"In enemy bullets of the proximity of the time of red traveling , we achieve the +100 of thousands of in one play ."
Failure of Google translate, but the gist is that you need to have loads of red bullets around you. There are similar achievements in other BH schmups.
I unlocked this during the final boss in Black Label - Black Novice mode.
Don't think it matters much, but for consistency I played through the entire game using the Zesshikai Over mode. This makes this very easy, at least in Novice.
When you get to the boss, just do your best to stay alive and this should unlock. If need be you could try to purposely stick close to clusters, but again this shouldn't be necessary. This should help you 1CC as well as unlock:
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