Polish Corridor gave Poland access to the sea at Danzig (Gdansk). There were many ethnic Germans living in the Polish Corridor. Hitler claimed that these people had the right to live in Germany. In Mein Kampf Hitler promised his readers that he would restore this land, taken by the Treaty of Versailles, to Germany.
Hitler started to make moves against Poland in March 1939 just as Germany invaded the rest of Czechoslovakia. Control of Czechoslovakia gave Hitler a southern border with Poland. Anti-Polish propaganda was published in Germany; this claimed that the Poles were mistreating Germans living in the Polish Corridor. Hitler wanted to use this as an excuse to �rescue his people�.
Britain promised to support Poland if it was attacked. This was intended as a warning to Hitler that appeasement had gone far enough. Chamberlain knew that Britain could never effectively help Poland. Poland was too far away for Britain to defend from Germany. Chamberlain hoped that he could still appease Hitler and avoid a major war.