diff --git a/docs/source/tutorial-contract-clauses.rst b/docs/source/tutorial-contract-clauses.rst
index 6f705cb37d..7957dd4d9f 100644
--- a/docs/source/tutorial-contract-clauses.rst
+++ b/docs/source/tutorial-contract-clauses.rst
@@ -136,8 +136,8 @@ and is included in the ``CommercialPaper.kt`` code.
                     val command = commands.requireSingleCommand<Commands.Move>()
                     val input = inputs.single()
                     requireThat {
-                        "the transaction is signed by the owner of the CP" by (input.owner in command.signers)
-                        "the state is propagated" by (outputs.size == 1)
+                        "the transaction is signed by the owner of the CP" using (input.owner in command.signers)
+                        "the state is propagated" using (outputs.size == 1)
                         // Don't need to check anything else, as if outputs.size == 1 then the output is equal to
                         // the input ignoring the owner field due to the grouping.
                     }
diff --git a/docs/source/tutorial-contract.rst b/docs/source/tutorial-contract.rst
index bb5f8cbe7a..abc5240532 100644
--- a/docs/source/tutorial-contract.rst
+++ b/docs/source/tutorial-contract.rst
@@ -438,8 +438,8 @@ logic.
               is Commands.Move -> {
                   val input = inputs.single()
                   requireThat {
-                      "the transaction is signed by the owner of the CP" by (input.owner in command.signers)
-                      "the state is propagated" by (group.outputs.size == 1)
+                      "the transaction is signed by the owner of the CP" using (input.owner in command.signers)
+                      "the state is propagated" using (group.outputs.size == 1)
                       // Don't need to check anything else, as if outputs.size == 1 then the output is equal to
                       // the input ignoring the owner field due to the grouping.
                   }
@@ -451,10 +451,10 @@ logic.
                   val received = tx.outputs.sumCashBy(input.owner)
                   val time = timestamp?.after ?: throw IllegalArgumentException("Redemptions must be timestamped")
                   requireThat {
-                      "the paper must have matured" by (time >= input.maturityDate)
-                      "the received amount equals the face value" by (received == input.faceValue)
-                      "the paper must be destroyed" by outputs.isEmpty()
-                      "the transaction is signed by the owner of the CP" by (input.owner in command.signers)
+                      "the paper must have matured" using (time >= input.maturityDate)
+                      "the received amount equals the face value" using (received == input.faceValue)
+                      "the paper must be destroyed" using outputs.isEmpty()
+                      "the transaction is signed by the owner of the CP" using (input.owner in command.signers)
                   }
               }
 
@@ -463,9 +463,9 @@ logic.
                   val time = timestamp?.before ?: throw IllegalArgumentException("Issuances must be timestamped")
                   requireThat {
                       // Don't allow people to issue commercial paper under other entities identities.
-                      "output states are issued by a command signer" by (output.issuance.party.owningKey in command.signers)
-                      "output values sum to more than the inputs" by (output.faceValue.quantity > 0)
-                      "the maturity date is not in the past" by (time < output.maturityDate)
+                      "output states are issued by a command signer" using (output.issuance.party.owningKey in command.signers)
+                      "output values sum to more than the inputs" using (output.faceValue.quantity > 0)
+                      "the maturity date is not in the past" using (time < output.maturityDate)
                       // Don't allow an existing CP state to be replaced by this issuance.
                       "can't reissue an existing state" by inputs.isEmpty()
                   }
@@ -531,7 +531,7 @@ is straightforward: we are simply using the ``Preconditions.checkState`` method
 built into the language. In fact *requireThat* is an ordinary function provided by the platform's contract API. Kotlin
 supports the creation of *domain specific languages* through the intersection of several features of the language, and
 we use it here to support the natural listing of requirements. To see what it compiles down to, look at the Java version.
-Each ``"string" by (expression)`` statement inside a ``requireThat`` turns into an assertion that the given expression is
+Each ``"string" using (expression)`` statement inside a ``requireThat`` turns into an assertion that the given expression is
 true, with an ``IllegalStateException`` being thrown that contains the string if not. It's just another way to write out a regular
 assertion, but with the English-language requirement being put front and center.
 
diff --git a/docs/source/tutorial-cordapp.rst b/docs/source/tutorial-cordapp.rst
index 2bf280416d..88d26da3b8 100644
--- a/docs/source/tutorial-cordapp.rst
+++ b/docs/source/tutorial-cordapp.rst
@@ -459,14 +459,14 @@ To check what validation is performed over the IOU data, have a look at the ``IO
 .. sourcecode:: kotlin
 
   // Generic constraints around the IOU transaction.
-  "No inputs should be consumed when issuing an IOU." by (tx.inputs.isEmpty())
-  "Only one output state should be created." by (tx.outputs.size == 1)
+  "No inputs should be consumed when issuing an IOU." using (tx.inputs.isEmpty())
+  "Only one output state should be created." using (tx.outputs.size == 1)
   val out = tx.outputs.single() as IOUState
-  "The sender and the recipient cannot be the same entity." by (out.sender != out.recipient)
-  "All of the participants must be signers." by (command.signers.containsAll(out.participants))
+  "The sender and the recipient cannot be the same entity." using (out.sender != out.recipient)
+  "All of the participants must be signers." using (command.signers.containsAll(out.participants))
 
   // IOU-specific constraints.
-  "The IOU's value must be non-negative." by (out.iou.value > 0)
+  "The IOU's value must be non-negative." using (out.iou.value > 0)
 
 **Once an IOU has been submitted:**