Which is the tallest construction in Japan?
Tokyo Tower?
OMEGA transmission mast (is it still standing)?
Or perhaps an other guyed mast in Japan?
Which is the tallest skyscraper, the tallest electricity pylon, the tallest bridge pillar and the tallest chimney in Japan?

Good question.I would like to know that as well

isnt the tallest steel structure tower the Tokyo tower?
and the tallest skyscraper the Yokohama Landmark tower?

The tallest construction in Japan is the mast of the OMEGA transmitter Shushi-Wan ( http://en.wikipedia.org/wiki/OMEGA_Transmitter_Shushi-Wan ). Has someone more data of it?