The 26-year-old Spanish striker spent the first half of the season on loan at Spanish second division side UCAM Murcia but is now making a permanent switch the Far East.
Juanma joined Hearts in June 2015 and netted 13 goals during his first season in Edinburgh, finishing as the club’s top scorer.
But he was deemed surplus to requirements this term and shipped out to Spain.
A spokesman for the Gorgie side said: “We wish him well in his new Japanese adventure.”
Tynecastle boss Ian Cathro has already allowed former Celtic hitman Tony Watt to return to Charlton after a disappointing loan stint, while former skipper Alim Ozturk has negotiated his release in order to join Turkish side Boluspor.
Cathro is keen to reshape his squad after replacing Robbie Neilson and has made veteran Northern Ireland centre-half Aaron Hughes and former Hamilton full-back Lennard Sowah his first two captures.