I'm gonna take a quick stab at this because I think it might have a fairly easy answer without getting too in depth. For all intents and purposes, the Imperial Japanese Navy didn't have ground forces during WW2 (they had some, but a negligible amount in the grand scheme of things) so if you're seeing land fighting during the war then that's likely the Imperial Japanese Army. To give you an idea of the disparity, the Japanese Navy totaled something like 1.3 million men whereas the Japanese Army had over 6 million.

The reason you might see the Japanese Navy mentioned a lot is because of their relative roles - the Japanese Navy was considered an elite force (they'd wiped the floor with the Russians just before World War 2 to prove that to the world) so they were tasked with offensive operations and were considered the primary threat. The Japanese Army was fanatical but not well equipped and was tasked with a largely defensive role in the fight against the U.S., holding a defensive perimeter. There was also a significant rivalry between the Japanese Army and Navy.

The Japanese Army relied on the Navy to keep its supply lines open so destroying the Japanese Navy was the primary goal in the Pacific for the Allies, to allow the island hopping campaign whereby large portions of the Japanese Army were simply bypassed and effectivity left as prisoners in the island fortresses they'd built. The battles of Midway and the Coral Sea ended the Japanese Navy as an offensive threat, Guadalcanal further eroded their operational capacity, their air wings were annihilated in the Philippine Sea, and the surface fleet was largely destroyed at Leyte Gulf. After that point the Navy was basically destroyed, turning instead to unconventional warfare like the kamikaze. In a sense the war was won once the Navy was destroyed but the hard work of proving that to the Japanese would be taking the few islands that absolutely couldn't be bypassed from the troops defending them.

Islands that couldn't be bypassed were largely garrisoned by the Japanese Army. Battles like Guadalcanal, Iwo Jima, and Okinawa were fought primarily against the troops of the Imperial Japanese Army. In that sense they were very involves.