South Africa won the COSAFA Cup with a 3-2 victory over Botswana in the final in Windhoek, Namibia on Saturday.
Da Gama and his charges - minus Brondy midfielder Lebogang Phiri - will have little time to celebrate. They leave OR Tambo International Aiport at 17h20 today on a 13-hour flight to Hong Kong. They will take a connecting flight to Nagano Prefecture before driving three hours to the city of Matsumoto.
The friendly - which serves as preparation for the Rio Olympics - will kick off at 12h30 (SA time) at the General Sports Stadium Alwin in Nagano.
"We are very grateful to the Japan Football Association for granting us the chance to play this all-important match," Da Gama said.
"We are now just over a month away from the Olympic Games and we need a few more matches to brush up on our game. We are happy with the work we have put in so far, moreso the achievement we got in the COSAFA Cup – it will go a long way in lifting the morale of the team.
"The game Japan is crucial in that it will help check how far we have come and what more needs to be done. A win will most certainly keep the positive momentum in the team going on."
Da Gama has faith his players will not suffer from fatigue in the Land of the Rising Sun.
"Yes, it is going to be a very long trip but such is international football, however we have a programme in place that will ensure that all the players are well rested and injury free ahead of the match.
"This is will be an exciting experience for the players and a greater test for all of us in our mission to building a strong South African Olympic team."
While Phiri is unavailable, the squad has been boosted by the addition of forward Thapelo Morena (Bloemfontein Celtic), midfielder Paseka Mako (Chippa United) and defender Mothiba Mvalo (Highlands Park).
SA U-23 squad going to Japan:
GOALKEEPERS:
1. Jody FEBRUARY Ajax Cape Town FC (SA)
2. Reyaad PIETERSE Supersport United FC (SA)
3. Nkosingiphile GUMEDE Golden Arrows FC (SA)
DEFENDERS
4. Tshepo RIKHOTSO Bloemfontein Celtic FC (SA)
5. Rivaldo COETZEE Ajax Cape Town FC (SA)
6. Abbubaker MOBARA Ajax Cape Town FC (SA)
7. Mothiba MVALO Highlands Park FC (SA)
8. Tebogo MOERANE Bidvest Wits FC (SA)
9. Tercious MALEPE Orlando Pirates FC (SA)
10. Siphesihle STUURMAN Vasco Da Gama FC (SA)
11. Thembela SIKHAKHANE Golden Arrows FC (SA)
MIDFIELDERS:
12. Gift MOTUPA Orlando Pirates FC (SA)
13. Paseka Mako Chippa United FC (SA)
14. Maphosa MODIBA Mpumalanga Black Aces FC (SA)
15. Deolin MEKOA Maritzburg United FC (SA)
16. Thembinkosi LORCH Orlando Pirates FC (SA)
STRIKERS:
17. Thabiso KUTUMELA Orlando Pirates FC (SA)
18. Menzi MASUKU Orlando Pirates FC (SA)
19. Judas MOSEAMEDI Mpumalanga Black Aces FC (SA)
20. Thapelo MORENA Bloemfontein Celtic FC (SA)