diff --git a/contracts/Proofs.sol b/contracts/Proofs.sol
index 399f83a..e856c50 100644
--- a/contracts/Proofs.sol
+++ b/contracts/Proofs.sol
@@ -50,7 +50,7 @@ contract Proofs {
     internal view
     returns (bool)
   {
-    bytes32 hash = blockhash(blocknumber);
+    bytes32 hash = blockhash(blocknumber - 1);
     return hash != 0 && uint(hash) % periods[id] == markers[id];
   }
 
diff --git a/test/Proofs.test.js b/test/Proofs.test.js
index c6a011f..1dcd350 100644
--- a/test/Proofs.test.js
+++ b/test/Proofs.test.js
@@ -45,7 +45,7 @@ describe("Proofs", function () {
     }
 
     async function minedBlockNumber() {
-      return await ethers.provider.getBlockNumber() - 1
+      return await ethers.provider.getBlockNumber()
     }
 
     async function mineUntilProofIsRequired(id) {