Commercial Comparison

Before looking at the chosen Japanese commercial, my first findings actually didn't mainly address Chicken. Instead it was rather about popular animated Japanese characters from Dragon Ball Z and One Piece, marketing merchandising like cups for drinks and ice. In a similar notion, the fashion and music celebrity Kyary Pamyu Pamyu has appeared in several clips, focusing especially on crushed ice drinks. While looking at Korean commercials, I only found one comparable advertisement, in which a famous model and actress behaves unsettlingly cute for a whole minute while holding and eating several KFC products.

The Japanese spot relies more on non-verbal communication. The message can be pretty well understood even if the viewer is unable to translate the writing. The commercial focusses on the simple notion that misfortune and negative thoughts can be diminished with the prospect of Kentucky Fried Chicken, bringing people together and raising the spirits. It heavily reenforces emotional engagement and collective values, showing three different groups (school kids, office workers, a family) that cling together and tough out their hardships as a team. No one has to work out their problems alone, and no one eats alone. The spot actually doesn't advertise any specific KFC product (although the people are shown eating various chicken-related products), and neither are prices, sets of special offers shown. Everything is lined out to make the viewer feel good about themselves and about KFC by combining the notion of teamwork with the brand.

The Korean spot tries to establish some kind of specific characters with the slightest grain of individual personality. Importance is put on the notion of family, as the mother seems a bit distressed upon the sudden disappearance of her daughter, who is shown buying her bucket of KFC in a store. She doesn't eat it alone though, but happily surprises her mother, who is absolutely delighted by the fast food chicken. The importance of eating together is stressed even further when two teenagers with no former importance appear in the last seconds to share the meal. The pattern of eating together is frequently shown in most Korean KFC spots. Although there isn't a comparable amount of deeply moving Schmaltz as in the Japanese Commercial, eating KFC is seen as a social event in Korea as well, be it with family, friends or colleagues. While a viewer who doesn't understand Korean will still easily know what brand is marketed, they will probably neither know which specific product is marketed nor how much 3500 won may be for a menu. Even the words "Herb garlic chicken" may be lost on the foreign viewer, since the pronounciation of Korean-English is slightly... different. So while the brand can still be recognized by anyone, the emotional effect (and most of the specific advertisement goals) are lost for foreign viewers in the Korean commercial, while anyone will be able to fully understand the Japanese one. Translating the japanese written messages may slightly further enrich the emotional experience, but in general, the feelings are well translated through the images.

A big difference in this (and many other Korean KFC commercials) is the frequent utilization and mention of garlic, a local Korean favorite. While the Japanese spots don't seem to particularly advertize one specific direction of flavor, garlic is present as a persuasive selling point in many Korean Commercials. Marketeers for the japanese consumer groups seem to take a larger emphasis on emotional attachment to the brand and inclusion of known and loved faces from the celebrity and animation scene.

Conclusion

Although both countries share many similarities, among others in terms of family importance, confucianistic values, westernization through the USA - especially since the second half of the 20th century - , this example should at least show that identical measures should not be used lightly for seemingly similar societies. Fast food as well as most other products work differently in every market. The same can be said about the context of advertisement reception and product consumption. Even when values are similar, a different approach of transmitting theses messages and appeasing to specific consumer needs may be necessary. 

One outstanding example of difference concerning KFC in both markets for example is the brands role in Japan for christmas. Since Japan has no historic ties to Christmas and barely any Christian believers, KFC has managed to tie a connection in the Japanese public mind between "The Holidays of Love" and fried chicken. Japanese people make reservations long beforehand, and on Christmas Eve, you will see lines of customers, waiting to take their Christmas Chicken (and KFC Christmas Cake, because apparently that has become a tradition as well). The company claims that the origin stems from a homesick foreigner, who wanted to eat Turkey for Christmas in ~1971, and chose Chicken as a substitute since Turkeys aren't really eaten in Japan. And it's not even as if the Japanese were treatin KFC for Christmas as a special Japanese thing. KFC has just managed to make them think that is what you eat for Christmas. 
One of the biggest holidays of the year is now associated with KFC in Japan because the company has managed to fill a market niche and take full of advantage. While you will see the occasional Christmas commercial spot for KFC in Korea (and any other country) as well, it will not have the same significance as for the Japanese.
No deeply intrinsic cultural values or differences between Japan and Korea are mainly responsible for this occurence only to happen in one of the countries. In the end, KFC seized an opportunity where it appeared and built upon it for over forty years.


Sources:
http://blogs.smithsonianmag.com/food/2012/12/why-japan-is-obsessed-with-kentucky-fried-chicken-on-christmas/
http://www.tofugu.com/2010/12/24/kfc-japan-christmas/