The player can select one from eight available national teams in Tecmo World Cup '90. Japan were included despite them failing to qualify for the World Cup in 1990. The game was an unofficial release, giving them the chance to include the team for appease Japanese players.
The following teams were selectable.
A later European revision of the game was released which included France (also non-qualifiers) in place of the USA and Spain in place of Japan.
Source: Wikipedia, "Tecmo World Cup '90", available under the CC-BY-SA License.