A depleted Black Stars side are hoping to upset the odds when they face the World Cup-bound Samurai Blue at Kanagawa's Nissan Stadium.
While the hosts will use the encounter to get in shape for next month's global showpiece in Russia, Kwesi Appiah's outfit are on a preparatory curve ahead of September's clash with Kenya in the 2019 Africa Cup of Nations qualifying.
"Japan are a team who can play good football, so we must prepare well and give all we’ve got in the match," Partey said, as reported by JFA.
"Despite it being a friendly match, it is important to go all out and win the match.
"The weather in Japan is not too hot nor is it too cold, so we are not worried about it.
"The team should be able to adjust to this weather and there should be no effect on our performance.
"We are looking forward for the match."
Wednesday's fixture will be the sixth match between Ghana and Japan at senior level.
From five previous encounters - all friendlies - the Samurai Blue hold a better record, having claimed wins on four occasions.
The Black Stars' only triumph came in 2006 when they stunned the Asians by a lone-goal.
The last meeting between the teams was in 2013 when Japan registered a 3-1 victory.