Sunwolves howling at the moon as Lions prowl

Tokyo - Japan's Sunwolves face a baptism of fire in Super Rugby after filling their playing roster only days ago and with their coach returning just in time from compassionate leave.

The new Tokyo franchise host the Johannesburg-based Lions on Saturday hoping to avoid a mauling after joining an expanded 18-team competition alongside Argentine side the Jaguares and South Africa's Kings.

The Sunwolves suffered a fresh setback last week when head coach Mark Hammett was forced to leave the team's training camp on Japan's honeymoon island of Okinawa following the death of his mother.

"Defence is likely to be the key," said Sunwolves captain Shota Horie, the Japan hooker who previously played for the Melbourne Rebels in 2013-14.

"We have to be mindful of that when we go and play and it will be important for the team to come together and play as one."

Hammett is scheduled to return to Japan on Friday after flying back to New Zealand for the funeral, having left his side's fine tuning to assistant coach Filo Tiatia.

With preparations already in disarray after failing to name their playing and coaching staff until late December, the Sunwolves are expected to face a pummelling against the southern hemisphere's hulking giants.

Hammett only completed his final 39-man squad earlier in the week, bringing in local prop Takuma Asahara and Tasman Makos wing Viliami Lolohea.

Also as part of a flurry of last-minute appointments, Atsushi Tanabe joins as backs and skills coach, making him Japan's first Super Rugby coach.

Ricoh Black Rams wing Amanaki Lotoahea misses out through injury, meanwhile, and the jet-heeled Akihito Yamada could yet leave the Sunwolves early in the season to play for Japan's sevens team at this year's Rio Olympics.

Japan, once the whipping boys of the World Cup, caused shockwaves by winning three of their four games at last year's tournament in England, including an astonishing 34-32 upset over two-time world champions South Africa.

However, the forward momentum gained under Australian coach Eddie Jones has since given way to inertia at national and Super level.

As the Sunwolves stalled over appointments, Japan officials also failed to name a stand-in for the Brave Blossoms to fill in until new coach Jamie Joseph arrives in August after his current job with the Highlanders ends.

Sunwolves hopes were dealt a further blow after several Japan World Cup stars snubbed the Wolves - among them national skipper Michael Leitch and Japan's new sporting pin-up, fullback Ayumu Goromaru, who opted to join the Reds in Queensland.

The Sunwolves warmed up for the season by beating a Japanese Top League select side 52-24 two weeks ago, but produced little to suggest the Lions will be quaking in their boots.