A breach of contract happens when one party doesn’t keep their part of the deal. By law, Judah owed his daughter-in-law a husband and a son. His failure to find her a husband was a breach.
Her solution (seducing him and conceiving his son) was another kind of breach. Tamar's act is a breach in patriarchy that silences women.
Scripture is full of those breaches.
It’s true that much of the Old Testament is disturbing stories of violence and oppression against women and other marginalized people. The Old Testament reflects the world in which it was written.
But what I find amazing are the cracks, the breaches in that world that many of the stories reveal.
The story of Tamar outwitting her father-in-law is a breach. Rahab the prostitute that saves herself and her family is a breach.
Ruth, the story of two women who find a way to survive in a man’s world is a breach.
The inclusion of these women in the genealogy of Jesus is a sign that the kingdom of God that Jesus brings is going to rip that breach even further.