After being unbeaten in 5 bouts (4 wins and a draw), Shingaki challenged Dodie Boy Peñalosa for the vacant IBF light flyweight title on December 10, 1983.
On his second defense, Shingaki fought Australia's Jeff Fenech on 26 April 1985 at the Hordern Pavilion in Sydney.
They met again on August 23 in the same year at the State Sports Centre, again in Sydney where once more, Shingaki was beaten, this time in 3 rounds.
In true Japanese tradition Shingaki never gave up but the fight was stopped after 3 rounds after he was ruled unfit to continue.
Shingaki, despite his injury was keen to continue, even shaping up showing he was willing to go on, but the doctor and referee wouldn't budge and the fight was over.