The Silver Sword is essentially about the children's journey, on their own, to reunite with their parents in Switzerland. It is therefore safe to conclude that the main theme of the story is Survival.
When the story begins, we meet Joseph Baliki who is imprisoned for teaching in his Polish language and turning a photo of Hitler to the wall. Notice that he, too, tries to survive the odds after his escape from prison. When the reader is introduced to the Baliki children, they are left on their own to fend for themselves after their mother is taken away by Germans. Ruth is forced to be mother to all of them and Edek becomes the bread-winner. Even later when they meet Jan, it is a fight to overcome hunger, the cold, the horror of guns and of the bombing all around them. It is a time of war and it is amazing that the children finally got their happy ending. Thankfully, there were also persons who aided their survival. These persons include, Ivan, The Barvarian Farmer and his wife and Joe Wolski, to name a few.
the theme 4 the the silver sword is about courage,surival,good vs evil and 4 working togther as a team.
The silver sword is a metaphor, a token for hope. As a reminiscence of their parents, it helps maintain connection with their family even though they got separated due to the war. The presence of the silver sword and the feeling it creates gives the children strength to bear the difficulties on their journey to find their parents while acting as a lucky charm for them to reach their goal. It reminds us that goals are achieved by the combined forces of faith, determination, commitment and luck (i.e.fortune). It's a story of resilience and success.
I would say that the theme of this book would be Survival or determination..Survival would be the main because it floods the entire book.