フォーミュラ・トヨタ
Takagi was heavily influenced by his father, a touring car driver. In the early 1980s he began racing karts, competing in his first championship kart race in 1987. After winning several All Japan National Kart A2 series races, Takagi ended his kart racing career in 1991 and began racing Formula Toyota in 1992. In 1993, he began competing in All Japan Formula Three, finishing 10th in his rookie season.