diff --git a/ikura/shim/src/cli.rs b/ikura/shim/src/cli.rs
index 9cb05945..4e391732 100644
--- a/ikura/shim/src/cli.rs
+++ b/ikura/shim/src/cli.rs
@@ -181,7 +181,7 @@ pub mod query {
         ///
         /// Hashes must be 32 bytes, hex-encoded, and prefixed with "0x".
         #[arg(value_name = "BLOCK_REF")]
-        pub block_ref: BlockRef,
+        pub block_ref: Option<BlockRef>,
 
         /// By default, if the block is not available (e.g. not yet produced), the shim will return immediately.
         ///
diff --git a/ikura/shim/src/cmd/query/mod.rs b/ikura/shim/src/cmd/query/mod.rs
index eb50e461..bafeb53e 100644
--- a/ikura/shim/src/cmd/query/mod.rs
+++ b/ikura/shim/src/cmd/query/mod.rs
@@ -23,9 +23,9 @@ pub async fn get_block_at(
     block: BlockParams,
 ) -> anyhow::Result<ikura_rpc::Block> {
     let maybe_hash = match block.block_ref {
-        BlockRef::Best => None,
-        BlockRef::Hash(h) => Some(h),
-        BlockRef::Number(n) => Some(match block.wait {
+        None | Some(BlockRef::Best) => None,
+        Some(BlockRef::Hash(h)) => Some(h),
+        Some(BlockRef::Number(n)) => Some(match block.wait {
             true => client.await_block_hash(n).await,
             false => client
                 .block_hash(n)