I have heard stories of long Akita memories, like the abused Akita that was rescued, went on to become an extremely goodnatured showdog and then one day in the ring began growling. the owner/handler and the judge were amazed (judge knew the dog) because this dog NEVER showed agression unless appropriate. then they look around, and at the edge of the ring is the abusing former owner. And it had been 4 or 5 years since the dog had last seen him.
on a more personal level, my first two Akitas always rememberd my mom, dad, sister and grandparents when they would come to visit me, sometimes with over 2 years between visits. my male even recognized my parents car by the sound of the engine (no, it had no distinctive sound that i coud ascertain) after not seeing it for a year or more.