SoftBank Ventures announced on the 22th that it invested 1 billion won ($900,000) in VCNC, a Korean startup.

Founded last February by five people including CEO Park Jae-wook, who got a B.A. in electronic engineering from Seoul National University, VCNC (Value Creators & Company) developed ‘Between’, an SNS for couples.

In a word, Between is an app that allows for all kinds of communication between a couple, including messages, photos, and notes. For example, a couple can use chat for private conversation, create an album where they can upload their photos, and use notes to send long text. A memory box can be used to store memorable moments.

Launched on October 22, Between highlighted a selling point that it is a communication and memory-sharing app for couples. Its subscribers reached 100,000 on the 13th of last month, only 3 weeks after the launch. Messages exchanged in a day are 760,000 and photos, 100,000. “The service use rate and duration are much higher and longer compared to other services because all the subscribers are couples,” said CEO Park.

A market targeting couples is still at an early stage despite its large potential. According to Park, there are 8 million couples in Korea, and they meet 3.6 times a week on average and spend 70,000 won ($65) per meeting. A market for couples, therefore, surly has great potential if his logic is taken.

VCNC’s market is not restricted to Korea. It will concentrate on the local market this year and start expanding globally next year. The first target is East Asia including Japan and China. Currently, Between is supported in Korean, English, Chinese and Japanese.

A closed service model like Between has already been proved in the United States. GroupMe, a service that allows for a chat or tracking only among those who have given consent to them, was sold to Skype for 85 million dollars only 1.5 year after launch. Beluga recently acquired by facebook and Fast Society all features closedness. A growing antipathy to existing SNSes among the public because of excessive openness played a critical role in their success.