diff --git a/polkadot/api/src/lib.rs b/polkadot/api/src/lib.rs
index a16781eb69..efe0f45220 100644
--- a/polkadot/api/src/lib.rs
+++ b/polkadot/api/src/lib.rs
@@ -28,12 +28,12 @@ extern crate substrate_state_machine as state_machine;
 extern crate error_chain;
 
 use client::backend::Backend;
-use client::blockchain::BlockId;
 use client::Client;
 use polkadot_runtime::runtime;
 use polkadot_executor::Executor as LocalDispatch;
 use substrate_executor::{NativeExecutionDispatch, NativeExecutor};
 use primitives::{AccountId, SessionKey};
+use primitives::block::Id as BlockId;
 use primitives::parachain::DutyRoster;
 
 error_chain! {
diff --git a/polkadot/primitives/src/block.rs b/polkadot/primitives/src/block.rs
index d71fa82e1c..987744baa6 100644
--- a/polkadot/primitives/src/block.rs
+++ b/polkadot/primitives/src/block.rs
@@ -23,6 +23,8 @@ use rstd::vec::Vec;
 use codec::{Input, Slicable};
 use transaction::UncheckedTransaction;
 
+pub use primitives::block::Id;
+
 /// Used to refer to a block number.
 pub type Number = u64;