Coach Javier Aguirre and his Japan squad are dealing with some behind-the-scenes distractions that could complicate their bid for a record fifth Asian Cup title.

The defending champion will compete in Group D with Jordan, 2007 champion Iraq and the Palestinian team for the tournament which opens on Friday.

After victories in 1992, 2000, 2004 and 2011, another title would solidify Japan's place as the region's powerhouse.