Like lumalo said, but also Poland also went to war with Czechoslovakia during the interwar period (1919) over Tesin Silesia. You can find many bourgeois nationalist sources saying the Czechs were the aggressors here, however the fundamental issue is that Tesin Silesia was an important conduit for western weapons reaching Poland for the fight against the Red Army. Also Poland broke a previous agreement for dual custody of the area by starting federal elections in Tesin Silesia. Similarly, the Czech workers in the area were actively blockading the railway because they supported the Soviets and the Poles would have loved to stop that.
Regardless, Polish nationalism was very crazy in this period. They went to war with all of their neighbors, including against independent governments in Ukraine. I think that in itself is very telling.
Like lumalo said, but also Poland also went to war with Czechoslovakia during the interwar period (1919) over Tesin Silesia. You can find many bourgeois nationalist sources saying the Czechs were the aggressors here, however the fundamental issue is that Tesin Silesia was an important conduit for western weapons reaching Poland for the fight against the Red Army. Also Poland broke a previous agreement for dual custody of the area by starting federal elections in Tesin Silesia. Similarly, the Czech workers in the area were actively blockading the railway because they supported the Soviets and the Poles would have loved to stop that.
Regardless, Polish nationalism was very crazy in this period. They went to war with all of their neighbors, including against independent governments in Ukraine. I think that in itself is very telling.