The two-time defending Commonwealth Cup winner, Spartak Moscow, will take on a strong field of 14 other champions from the former Soviet republics, plus the Russian Olympic team, in a weeklong soccer tournament starting Sunday.


The 16-team field is divided into four groups of four with winners from each group advancing to the semifinals Thursday. The final will be played Saturday at the CSKA indoor stadium.


For the first time in the three years of the Commonwealth Cup, there will be representatives from each former republic. The two previous times, Ukraine's champion, Dinamo Kiev, was absent from the tournament. This time, however, with tensions between Moscow and Kiev easing somewhat, the organizers were able to put together a complete lineup.


Dinamo Kiev still refused to participate, citing its dislike of playing indoors. In its place this year, Ukraine sent its runner-up club, Shakhter Donetsk.


Teams will have different reasons for playing in this competition, according to coaches and officials. Some have come to Moscow with the sole purpose of winning, others see it more as preparation for the remainder of the soccer season.


The Russian champion Spartak, which regularly makes up the bulk of the national-team players, will be gunning for its third Commonwealth Cup title. The team has just returned from a series of indoor tournaments in Europe with less than satisfactory results. In its first exhibition game in Moscow prior to the competition, Spartak redeemed itself in the eyes of the home fans by crushing Shirak Gumri, the Armenian champion, 5-1.


As usual, Spartak will be challenged by teams from countries with strong soccer traditions, such as Ukraine, Georgia, Belarus and Lithuania. However, there might be some surprises from other, less known soccer countries, like Uzbekistan, which last year shocked the soccer world by winning the gold at the Asian Games in Japan.


"The difference in soccer styles and cultures is what made the old Soviet soccer unique and exciting," said Nikita Simonian, vice president of the Russian Soccer Union and a former player for the Soviet national team.


Moscow's fans will have a fresh look at a number of teams, including Shakhter, which has a new head coach, Vladimir Salkov, and Georgian champion Dinamo Tbilisi, which brought in a few new players. "We came here to test our guys, to see other teams and have some fun," said Sergo Kutivadze, the head coach of the Tbilisi team.


Belarus' Dinamo Minsk, on the other hand, is preparing for a serious battle. "It is important for us to do well here," said Ivan Schekin, Minsk's head coach.


Here are some key match-ups at CSKA Stadium and Dinamo Stadium:


Sunday at CSKA: Dinamo Tbilisi (Georgia) vs. Russian Olympic team, 5 P.M.; Spartak Moscow (Russia) vs. Sitora (Tajikistan), 7 P.M.


Monday at CSKA: Dinamo Minsk (Belarus) vs. Kant-Oil (Kyrgyzstan) 5 P.M.; Spartak Moscow vs. Neftchi Baku (Azerbaijan), 7 P.M.


Monday at Dinamo: Dinamo Tbilisi vs. Zimbrul Kishinev (Moldova), 6 P.M.


Tuesday at CSKA: Spartak Moscow vs. Zhalgiris Vilnius (Lithuania), 7 P.M.


Tuesday at Dinamo: Dinamo Tbilisi vs. Elimai (Kazakhstan), 6 P.M.