Two self-made South Korean billionaires have pledged to give away half their fortunes.

Kim Beom-su, the founder of South Korea’s biggest messaging app KakaoTalk, announced this month he will donate more than half his estimated $9.6 billion assets to try to “solve social issues”.

Kim Bong-jin of food-delivery app Woowa Brothers and his wife, Bomi Sul, have also signed the Giving Pledge. They are the first South Koreans to join the philanthropic campaign which was set up by Bill and Melinda Gates, alongside Warren Buffett, for billionaires to give away at least half their wealth.

In his Giving Pledge statement, Kim of Woowa Brothers described his “humble beginning” on a small island.

His parents ran a small restaurant, where he slept at night, and as a teenager he gave up his dream of attending an art high school, enrolling instead in a cheaper vocational school.

Wealth, he said, had value when it was used for “the greatest benefit of the least advantaged members of society”.

Rather than keeping the entirety of their fortune, Kim and his wife said in their statement: “We are certain that this pledge is the greatest inheritance that we could provide for our children.”

Neither of the billionaire Kims, who were born to working-class families, has so far provided a precise timeline for their pledged donations.

More than 200 super-wealthy from around the world have signed the Giving Pledge, according to its website.