The Australian-born chef has stepped away to 'pursue other interests', details of which have yet to be announced.
Shonhan, who opened the first Bone Daddies ramen bar in London in 2012 with his business partner Demetri Tomazos, has played an important role in building up London's now-booming Japanese casual dining scene.
The pair went on to open bao bar Flesh and Buns in 2013 and Japanese-inspired Shack-Fuyu in 2015.
Shonhan's departure comes after he launched his first international restaurant separate to Bone Daddies, Japanese-inspired steakhouse Netsu, in Dubai’s Mandarin Oriental Jumeira hotel in 2019.
“I am very lucky to have had such amazing and supportive partners who helped build the business we have together,” Shonhan says in a statement.
“The future of [Bone Daddies] is in great hands and I look forward to watching management continue to grow it in ways that I only could have dreamt back in 2012.
“I think there are few occasions when business partners part ways positively and with goodwill. I am proud that whilst I am leaving the business, my business partners and teams will remain great friends.”
The Bone Daddies group now runs six London ramen bars, two Flesh and Buns sites and one Shack-Fuyu restaurant.
“We wish Ross all the best with his new endeavours and are confident that our friendship and his legacy will continue to play a large role in the Bone Daddies of the future,” says Tomazos.