The premium and limited-edition bananas are harvested in the Philippines at over 500 meters above sea level. This apparently helps the high-end ‘nanas to grow to about 200 grams — double of your average banana.
However, all this bananness does not come cheap, as the few that were offered cost around 590 yen ($5.80) each. If you were able to get one, consider yourself lucky. Just make sure to use it before it browns, or you won’t be able to read the serial number. The banana bread will be awesome though.