Okada and Umeda, who work for an agency called Asatsu-DK, beat teams from 13 other countries, who were challenged to create and present a campaign against human trafficking.
Silver went to the UK team, Leila Mountford and Kate Sloan from Weber Shandwick, and bronze to the Austria team, Pepita Adelman and Doria Steiner of Ketchum.
The teams presented this morning to judges Michael Frohlich, the UK head of Ogilvy PR and MD of its EMEA consumer marketing practice; Pascal Beucler, chief strategy officer at MSLGroup; and Marnie Kontovraki, global consumer PR officer at Heineken.
ICCO and co-sponsors Golin, H+K Strategies, Ketchum and Ogilvy PR launched the Young PR Lions competition this year to show how PR is used to engage audiences with an organisation or a specific topic that the client is dealing with.
Francis Ingham, ICCO chief executive, said: "I would like to congratulate the winners: their agency and their families should be proud of them. I would also like to applaud all this year’s contestants, who can rightfully regard themselves as the best young PR creatives in their respective countries.
"We are grateful to the festival and our agency co-sponsors for giving us the opportunity to get involved with this amazing competition, and already look forward to hosting the Young PR Lions 2015."
The winners will be presented with the Gold Medal tonight at the Creative Effectiveness, Promo & Activation, PR and Direct Lions Awards.
While Japan has claimed the top prize in the Young PR Lions, it faces tougher odds in the main contest, having secured just four nominations compared with 11 for the UK and one for Austria. The US has the most with 35, followed by Brazil with 18 – for more details see our shortlist story.