Japan v Palestine: Aguirre's men begin title defence
The four-time winners defeated this year's hosts, Australia, in the 2011 final and enter the 2015 showpiece as favourites.
Japan have not had the ideal preparation, though, with a disappointing 2014 World Cup campaign seeing them fail to progress from the group stages.
And new coach Javier Aguirre has become embroiled in a match-fixing investigation dating back to a La Liga game in 2011.
Midfielder Keisuke Honda - one of the team's European stars - said his team will be taking nothing for granted in the tournament.
"We are expecting some very difficult games at the Asian Cup," Honda said.
"All teams are strong. [Complacency] is the great enemy."
Japan have won four of their six international friendlies following the World Cup, including a 2-1 win over Australia.
They beat Auckland City 2-0 earlier this month in Cessnock, with Yasuhito Endo and Shinji Okazaki getting on the scoresheet.
The form of Mainz striker Okazaki and midfield pair Honda and Shinji Kagawa is likely to be crucial to Japan's chances.
The 54th-ranked nation are without experienced defender Atsuto Uchida, though.
Coach Aguirre said before the tournament: "Japan is always one of the favourites in this tournament.
"If we win the Asian Cup, we can tackle the rest of 2015 feeling refreshed."
Palestine, who are ranked 115th, have never featured at the Asian Cup before.
They qualified after winning the AFC Challenge Cup in the Maldives but will enter this clash as significant underdogs.
Palestine have played seven friendlies since winning the Challenge Cup, winning four.
Ahmed Al Hassan became coach of the nation in October, replacing Jamal Mahmoud, and striker Ashraf Al Fawaghra said reaching the tournament is significant for the nation.
"This is a historic occasion for us as it is our first Asian Cup," he told FIFA's website.
"Our goal is to let the world know that the Palestinian national team are moving forward, despite the difficulties facing us.
"We want to convert the messages that the Palestinian players have the right to play and develop."