diff --git a/specs/phase1/shard-fork-choice.md b/specs/phase1/shard-fork-choice.md
index b1fc3080e..6c431a68d 100644
--- a/specs/phase1/shard-fork-choice.md
+++ b/specs/phase1/shard-fork-choice.md
@@ -169,7 +169,7 @@ def on_shard_block(store: Store, shard_store: ShardStore, signed_shard_block: Si
     )
 
     # Check the block is valid and compute the post-state
-    assert verify_shard_block_message(beacon_parent_state, shard_parent_state, shard_block, shard_block.slot, shard)
+    assert verify_shard_block_message(beacon_parent_state, shard_parent_state, shard_block)
     assert verify_shard_block_signature(beacon_parent_state, signed_shard_block)
 
     post_state = get_post_shard_state(beacon_parent_state, shard_parent_state, shard_block)
diff --git a/specs/phase1/shard-transition.md b/specs/phase1/shard-transition.md
index fe3223933..c62b059ee 100644
--- a/specs/phase1/shard-transition.md
+++ b/specs/phase1/shard-transition.md
@@ -43,27 +43,26 @@ def compute_shard_transition_digest(beacon_parent_state: BeaconState,
 ### Shard block verification functions
 
 ```python
-def verify_shard_block_message(beacon_state: BeaconState,
+def verify_shard_block_message(beacon_parent_state: BeaconState,
                                shard_parent_state: ShardState,
-                               block: ShardBlock,
-                               slot: Slot,
-                               shard: Shard) -> bool:
+                               block: ShardBlock) -> bool:
     # Check `shard_parent_root` field
     assert block.shard_parent_root == shard_parent_state.latest_block_root
     # Check `beacon_parent_root` field
-    beacon_parent_block_header = beacon_state.latest_block_header.copy()
+    beacon_parent_block_header = beacon_parent_state.latest_block_header.copy()
     if beacon_parent_block_header.state_root == Root():
-        beacon_parent_block_header.state_root = hash_tree_root(beacon_state)
+        beacon_parent_block_header.state_root = hash_tree_root(beacon_parent_state)
     beacon_parent_root = hash_tree_root(beacon_parent_block_header)
     assert block.beacon_parent_root == beacon_parent_root
     # Check `slot` field
-    next_slot = Slot(slot + 1)
-    offset_slots = compute_offset_slots(get_latest_slot_for_shard(beacon_state, shard), next_slot)
-    assert slot in offset_slots
+    shard = block.shard
+    next_slot = Slot(block.slot + 1)
+    offset_slots = compute_offset_slots(get_latest_slot_for_shard(beacon_parent_state, shard), next_slot)
+    assert block.slot in offset_slots
     # Check `shard` field
     assert block.shard == shard
     # Check `proposer_index` field
-    assert block.proposer_index == get_shard_proposer_index(beacon_state, slot, shard)
+    assert block.proposer_index == get_shard_proposer_index(beacon_parent_state, block.slot, shard)
     # Check `body` field
     assert 0 < len(block.body) <= MAX_SHARD_BLOCK_SIZE
     return True