diff --git a/specs/sharding/beacon-chain.md b/specs/sharding/beacon-chain.md
index 0249590b8..f54394275 100644
--- a/specs/sharding/beacon-chain.md
+++ b/specs/sharding/beacon-chain.md
@@ -520,7 +520,7 @@ def get_start_shard(state: BeaconState, slot: Slot) -> Shard:
     """
     Return the start shard at ``slot``.
     """
-    epoch = compute_epoch_at_slot(Slot(_slot))
+    epoch = compute_epoch_at_slot(Slot(slot))
     committee_count = get_committee_count_per_slot(state, epoch)
     active_shard_count = get_active_shard_count(state, epoch)
     return committee_count * slot % active_shard_count