This sneaky sub attack almost changed the outcome of Pearl Harbor

The attack on Pearl Harbor was mostly an aerial sucker punch.

But history often forgets the role of Japanese submarines.

Just before adding the finishing touches to his sneaky plan, Japanese navy Adm. Yamamoto caved into his fleet's air-surface rivalry and drew up plans to involve sailors assigned to conventional ships.

Related: The Navy made these incredible photos to show present day Pearl Harbor compared to the day of the attack

"The Japanese air arm was going to get all the glory in the Pearl Harbor attack, and the surface fleet sailors were unhappy about this, they wanted to get in on the action," said author and historian Dan King in the video below. "But they couldn't send battleships, cruisers, and destroyers to Pearl Harbor, so the next best thing was to send in submarines.

As it turns out, Yamamoto was no stranger to intra-service rivalry and glory hogging. His promotion of force projection through gunboat diplomacy is a result of the Japanese Army-Navy rivalry.

He fought against political opponents in the Army who only wanted the Navy for the logistical support of invading forces, transport, and supply runs.

Yamamoto settled on the 80-foot Type A Ko-hyoteki — or "Midget" — submarine for the attack. The small two-person vessels were armed with only a pair of torpedoes and sent to lay dormant on the harbor floor until the air raid began.

However, in early Dec. 7, before the attack kicked off, an American cargo ship spotted one of these small subs heading to its position on the South end of Oahu. Members of the cargo ship alerted the USS Ward (DD-139), who's commander immediately called its crew to general quarters.

Two gun blasts and several depth charges later reduced the sub to scrap, and America officially drew first blood. But amazingly, the attack was treated as an isolated incident and didn't raise any flags of a larger invasion.

This American Heroes Channel video shows how the events played out during the early hours of the attack on Pearl Harbor.

Watch: