Josie Tada, from Samoa, has been living in Japan for the past 26 years and is set to be in the crowd at Kumagaya to watch the must-win clash.
It will be the first time the countries have played against each other.
"My husband is Japanese. He was a Japanese volunteer in Samoa when we met each other, and we got married then came to live in Japan," she said.
The mix of two different cultures took some getting used to, she said.
"At first it was a bit difficult, Japanese people don't really know about island culture, but it is getting better and better. The people are lovely, and the food is great."
Josie said she loves the Japanese people.
"They are very kind and generous. They often share things with us. The living is very nice.
"There is a big Samoan community in Tokyo, so you can stay connected with your culture.
"We get together regularly, often once a month, in a park or at the embassy to talk and plan. Recently we had a big preparation for this event, the Rugby World Cup in Japan."
Josie, from Alafua, goes back to Samoa to see friends and family regularly, although her husband, Tomoharu Tada, has never returned after his three-year stint of service.
"But he always cheers for Samoa."
They have two children - "half Japanese-Samoans" she calls them - and she tries to keep the language and culture of Samoa alive for them
The game will be a once-in-a-lifetime match, says Josie. She will be there with her Samoan cousin, Malaga Leota, the scrum coach of the NZ Defence Forces rugby team, currently in Japan.
"I will be waving my flag from the crowd. It's a once in a lifetime, seeing a World Cup, especially one here in Japan and seeing Samoa play.
"This will be a big game for us. It will be great to see. I will be there. Bring it on."
It's been almost 25 years since Samoa made it to the quarter final of a rugby world cup and they face a tough challenge to advance from Pool A - with Ireland, Scotland and hosts Japan all ranked inside the world's top 10.
The Manu are ranked 16th.
Samoa must beat the 20th-ranked Russians if they're to give themselves a chance of progressing to the knockout stages of the tournament.
Samoa's match against Russia will kick off at 10:15pm New Zealand time. It will be 11.15pm in Apia.