Complex sentence: At the 2012-2013 Grand Prix Final, Takahashi made history once again as the first Japanese man to win a gold medal in the event, an addition to his previous accomplishment of being the first Japanese man to medal at the event in 2005.
Split into simpler sentences: At the 2012-2013 Grand Prix Final, Takahashi made history once again as the first Japanese man to win a gold medal in the event. This adds to his previous accomplishment of being the first Japanese man to medal at the event in 2005.