World Rugby has information on every international match available here, however a little digging reveals that they actually pull the data in from a publicly accessible but entirely undocumented API. I wrote some Python code to allow me to scrape all the information possible from that API, which you can find in my PyRugby package.
With all the data scraped and loaded into a local PostgreSQL database I decided to start by looking at when each nation was first represented internationally.
Some points to note about this data:
“International” teams are not limited to those corresponding to sovereign nations. Several teams - including England, Wales, Scotland, Ireland, and Hong Kong - compete at international level representing smaller subdivisions of nations.
The first appearance is not necesarily a test match against another international team. Romania for example are listed as first playing against a US Army side and the USSR made their first outing against Romanian club side RC Grivita.
Early matches were decided on goals, but in cases of no goals being scored then the winner was decided by the number of tries. These results are coded as wins/losses but the score appears as 0-0. This is noticeable on-hover when viewing the interactive map linked below.
The USSR, Yugoslavia, Czechoslovakia and Arabian Gulf teams represented combinations of current nations and their first appearances are considered twice - once as part of the combined team, and once independently.
Some constituent nations competed independently from the whole before the breakup of the overarching state - for example Georgia competed as early as the late 80s.
Some constituent nations of those multi-nation states are yet to be represented independently and thus appear to lose representation in the video below.
The Rhodesia team is considered a distinct entity from the Zimbabwe team, although they both represent the same geographical nation.
East Germany is discounted, as rugby was played in Germany both before and after as a united Germany.
I took geo data from Natural Earth and created a custom set using sovereign nations where possible but incorporating dependencies and subdivisions where necessary. I computed centroids for this data using mapshaper. You can find the geo data in my map-data repo.
I initially wanted to produce an interactive Plotly chart with a slider for each year, however I found that using the choroplethmapbox trace type incorporating more than a handful of years created unfeasibly large files.
As a result I decided to create png images of every year and stitch them together into the a short video using iMovie.
I also created an interactive chart of the situation as it stands in 2020 (so no info on USSR etc) which you can find here