ISO book: surrender the galaxy to a planet of warriors

[Sepp]

hello
Looking for this book - starts with a fellow in disguise on an alien planet, espionage for the galactic federation, playing a strategy game with the natives to gain information.

The natives know about humans and discover him, plan to conquer the galaxy.
Along the way he falls in love with an alien woman.

He realizes they will likely prevail and to spare endless bloodshed recommends the galaxy surrender to them.

thanks

 

[Sepp]

OK I found it
Second Game by Charles V. De Vet , Katherine MacLean

thanks

 

[monkeypooper]

Wow that was fast