I don't think this is a true mate in three. I don't want to spoil the puzzle for others so the rest of my comments are written in white on white ... select the text to read it:
the solution as given on the link is 1...Ne4 2.Be1 defending the obvious mate 2...Qf2+ 3.Bxf2 Nd2#. However what about -- 1...Ne4 2.Be3 and now I don't see a way to mate in three, for example 2....Qxe3 3.c3 and there is no way for Black to deliver mate on the next move. Have I missed something
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from a game in 1909
black moves - mate in 3
for a solution : see here