A blood oath isn't good enough for a California appeals court.

The Fourth District Court of Appeal in Santa Ana agreed with a lower court Tuesday when it ruled that a contract written in blood between two Korean businessmen is unenforceable.

In October 2004, Jinsoo Kim and his friend Stephen Son were out drinking at a sushi restaurant and karaoke bar when Son asked the waiter for a safety pin, pricked his finger and wrote the contract on a piece of paper — in blood and in Korean characters.

Under the deal, Son promised to repay Kim roughly $170,000 for money Kim lost investing in Son's companies.

The translated note read: "Sir, please forgive me. Because of my deeds you have suffered financially. I will repay you to the best of my ability."

Son later added similar promises to the note in ink, according to court papers. Kim sued his friend in 2006 to collect.

But a judge — and now the appeals court — said the claim was invalid.

"We conclude the trial court properly decided Kim's lawsuit was based entirely on a gratuitous unenforceable promise," the appeals court ruled.