diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 99f7ad3..4210b23 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -33,9 +33,9 @@ repos:
     hooks:
     - id: mypy
       pass_filenames: false
-      args: [.]
+      args: [--package=pytket.phir, --package=tests]
       additional_dependencies: [
         pytest,
+        pytket==1.20.1,
         types-setuptools,
-        pytket,
       ]
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..98b123e
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,7 @@
+.PHONY: tests, lint
+
+tests:
+	pytest -s -x -vv tests/test*.py
+
+lint:
+	pre-commit run --all-files
diff --git a/pyproject.toml b/pyproject.toml
index aafb143..c60e2c1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -16,3 +16,4 @@ where = ["."]
 pythonpath = [
   "."
 ]
+filterwarnings = ["ignore:::lark.s*"]
diff --git a/pytket/phir/main.py b/pytket/phir/main.py
index bca21dd..a8d37c1 100644
--- a/pytket/phir/main.py
+++ b/pytket/phir/main.py
@@ -1,10 +1,29 @@
-"""This is the main module of the pytket-phir package."""
+"""
+NOTE: Just a placeholder to allow convenient testing of the flows
+"""
 
+from pytket.circuit import Circuit
+from pytket.qasm.qasm import circuit_from_qasm
 
-def hello_world() -> str:
-    """Print 'Hello, world!' to the console."""
-    hw = "Hello, World!"
-    return hw
+from .sharding.sharder import Sharder
 
+# Load a qasm circuit and parse
+#    ,=""=,
+#   c , _,{
+#   /\  @ )                 __
+#  /  ^~~^\          <=.,__/ '}=
+# (_/ ,, ,,)          \_ _>_/~
+#  ~\_(/-\)'-,_,_,_,-'(_)-(_)
+circuit: Circuit = circuit_from_qasm("tests/data/qasm/baby.qasm")
 
-print(hello_world())  # noqa: T201
+# https://cqcl.github.io/tket/pytket/api/circuit_class.html
+
+# Just a little debugging fun
+print("Input circuit:")
+print(circuit)
+print()
+
+sharding_output = Sharder(circuit).shard()
+
+print("Sharding output:")
+print(sharding_output)
diff --git a/pytket/__init__.py b/pytket/phir/sharding/__init__.py
similarity index 100%
rename from pytket/__init__.py
rename to pytket/phir/sharding/__init__.py
diff --git a/pytket/phir/sharding/shard.py b/pytket/phir/sharding/shard.py
new file mode 100644
index 0000000..0ff4cb8
--- /dev/null
+++ b/pytket/phir/sharding/shard.py
@@ -0,0 +1,23 @@
+from dataclasses import dataclass
+
+from pytket.circuit import Command
+from pytket.unit_id import UnitID
+
+
+@dataclass
+class Shard:
+    """
+    A shard is a logical grouping of operations that represents the unit by which
+    we actually do placement of qubits
+    """
+
+    # The schedulable command of the shard
+    primary_command: Command
+
+    # The other commands related to the primary schedulable command, stored
+    # as a map of bit-handle (unitID) -> list[Command]
+    sub_commands: dict[UnitID, list[Command]]
+
+    # A set of the other shards this particular shard depends upon, and thus
+    # must be scheduled after
+    depends_upon: set["Shard"]
diff --git a/pytket/phir/sharding/sharder.py b/pytket/phir/sharding/sharder.py
new file mode 100644
index 0000000..b3e9cf1
--- /dev/null
+++ b/pytket/phir/sharding/sharder.py
@@ -0,0 +1,81 @@
+from pytket.circuit import Circuit, Command, Op, OpType
+from pytket.unit_id import UnitID
+
+from .shard import Shard
+
+NOT_IMPLEMENTED_OP_TYPES = [OpType.CircBox, OpType.WASM]
+
+
+class Sharder:
+    """
+    The sharder class is responsible for taking in a circuit in TKET representation
+    and converting it into shards that can be subsequently handled in the
+    compilation pipeline.
+    """
+
+    def __init__(self, circuit: Circuit) -> None:
+        self._circuit = circuit
+        print(f"Sharder created for circuit {self._circuit}")
+        self._pending_commands: dict[UnitID, list[Command]] = {}
+        self._shards: list[Shard] = []
+
+    def shard(self) -> list[Shard]:
+        """
+        Performs the sharding algorithm on the circuit the Sharder was initialized
+        with, returning the list of Shards needed to schedule
+        """
+        print("Sharding begins....")
+        # https://cqcl.github.io/tket/pytket/api/circuit.html#pytket.circuit.Command
+        for command in self._circuit.get_commands():
+            self._process_command(command)
+        return self._shards
+
+    def _process_command(self, command: Command) -> None:
+        """
+        Handles a given TKET command (operation, bits, etc) according to the type
+        and the extant context within the Sharder
+        """
+        print("Processing command: ", command.op, command.op.type, command.args)
+        if command.op.type in NOT_IMPLEMENTED_OP_TYPES:
+            msg = f"OpType {command.op.type} not supported!"
+            raise NotImplementedError(msg)
+
+        if self.should_op_create_shard(command.op):
+            print(f"Building shard for command: {command}")
+            self._build_shard(command)
+        else:
+            self._add_pending_command(command)
+
+    def _build_shard(self, command: Command) -> None:
+        """
+        Creates a Shard object given the extant sharding context and the schedulable
+        Command object passed in, and appends it to the Shard list
+        """
+        shard = Shard(command, self._pending_commands, set())
+        # TODO: Dependencies!
+        self._pending_commands = {}
+        self._shards.append(shard)
+        print("Appended shard:", shard)
+
+    def _add_pending_command(self, command: Command) -> None:
+        """
+        Adds a pending sub command to the buffer to be flushed when a schedulable
+        operation creates a Shard.
+        """
+        # TODO: Need to make sure 'args[0]' is the right key to use.
+        if command.args[0] not in self._pending_commands:
+            self._pending_commands[command.args[0]] = []
+        self._pending_commands[command.args[0]].append(command)
+
+    @staticmethod
+    def should_op_create_shard(op: Op) -> bool:
+        """
+        Returns `True` if the operation is one that should result in shard creation.
+        This includes non-gate operations like measure/reset as well as 2-qubit gates.
+        """
+        # TODO: This is almost certainly inadequate right now
+        return (
+            op.type == OpType.Measure
+            or op.type == OpType.Reset
+            or (op.is_gate() and op.n_qubits > 1)
+        )
diff --git a/pytket/phir/utils.py b/pytket/phir/utils.py
deleted file mode 100644
index 4114ecb..0000000
--- a/pytket/phir/utils.py
+++ /dev/null
@@ -1,6 +0,0 @@
-"""Utility functions for the pytket-phir package."""
-
-
-def add_numbers(a: int, b: int) -> int:
-    """Add two numbers and returns the result."""
-    return a + b
diff --git a/requirements.txt b/requirements.txt
index 214e0e8..c602e38 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,3 +7,4 @@ pytest==7.4.2
 ruff==0.0.291
 sphinx==7.2.6
 wheel==0.41.2
+pytket==1.20.1
diff --git a/ruff.toml b/ruff.toml
index 7dc820d..c66ae97 100644
--- a/ruff.toml
+++ b/ruff.toml
@@ -42,11 +42,19 @@ select = [
   "YTT",  # flake8-2020
 ]
 
-ignore = []
+ignore = [
+  "T201", # no prints flake-8
+  "FIX002", # Allow todos
+  "TD002", # Allow no author todos
+  "TD003", # allow todos with no issues
+]
 
 [per-file-ignores]
 "__init__.py" = ["F401"]  # module imported but unused
-"tests/*"     = ["S101"]  # Use of `assert` detected
+"tests/*"     = [
+    "S101", # Use of `assert` detected
+    "PLR2004" # Magic constants
+  ]
 
 [pydocstyle]
 convention = "google"
diff --git a/tests/data/qasm/baby.qasm b/tests/data/qasm/baby.qasm
new file mode 100644
index 0000000..72a521b
--- /dev/null
+++ b/tests/data/qasm/baby.qasm
@@ -0,0 +1,11 @@
+OPENQASM 2.0;
+include "hqslib1.inc";
+
+qreg q[2];
+creg c[2];
+
+h q[0];
+h q[1];
+CX q[0], q[1];
+
+measure q->c;
diff --git a/tests/data/qasm/bv_n10.qasm b/tests/data/qasm/bv_n10.qasm
new file mode 100644
index 0000000..63775cc
--- /dev/null
+++ b/tests/data/qasm/bv_n10.qasm
@@ -0,0 +1,47 @@
+//@author Raymond Harry Rudy rudyhar@jp.ibm.com
+//Bernstein-Vazirani with 10 qubits.
+//Hidden string is 111111111
+OPENQASM 2.0;
+include "qelib1.inc";
+qreg qr[10];
+creg cr[9];
+h qr[0];
+h qr[1];
+h qr[2];
+h qr[3];
+h qr[4];
+h qr[5];
+h qr[6];
+h qr[7];
+h qr[8];
+x qr[9];
+h qr[9];
+barrier qr[0],qr[1],qr[2],qr[3],qr[4],qr[5],qr[6],qr[7],qr[8],qr[9];
+cx qr[0],qr[9];
+cx qr[1],qr[9];
+cx qr[2],qr[9];
+cx qr[3],qr[9];
+cx qr[4],qr[9];
+cx qr[5],qr[9];
+cx qr[6],qr[9];
+cx qr[7],qr[9];
+cx qr[8],qr[9];
+barrier qr[0],qr[1],qr[2],qr[3],qr[4],qr[5],qr[6],qr[7],qr[8],qr[9];
+h qr[0];
+h qr[1];
+h qr[2];
+h qr[3];
+h qr[4];
+h qr[5];
+h qr[6];
+h qr[7];
+h qr[8];
+measure qr[0] -> cr[0];
+measure qr[1] -> cr[1];
+measure qr[2] -> cr[2];
+measure qr[3] -> cr[3];
+measure qr[4] -> cr[4];
+measure qr[5] -> cr[5];
+measure qr[6] -> cr[6];
+measure qr[7] -> cr[7];
+measure qr[8] -> cr[8];
diff --git a/tests/data/qasm/cond_1.qasm b/tests/data/qasm/cond_1.qasm
new file mode 100644
index 0000000..6dfe4a5
--- /dev/null
+++ b/tests/data/qasm/cond_1.qasm
@@ -0,0 +1,16 @@
+OPENQASM 2.0;
+include "hqslib1.inc";
+
+qreg q[1];
+creg c[2];
+
+h q;
+measure q[0]->c[0];
+reset q;
+if (c==1) h q;
+if (c<1) h q;
+if (c>1) h q;
+if (c<=1) h q;
+if (c>=1) h q;
+if (c!=1) h q;
+measure q[0]->c[0];
diff --git a/tests/data/qasm/simple.qasm b/tests/data/qasm/simple.qasm
new file mode 100644
index 0000000..9ff7b72
--- /dev/null
+++ b/tests/data/qasm/simple.qasm
@@ -0,0 +1,11 @@
+OPENQASM 2.0;
+include "qelib1.inc";
+qreg q[1];
+creg c[1];
+
+h q[0];
+h q[0];
+h q[0];
+h q[0];
+h q[0];
+measure q->c;
diff --git a/tests/sample_data.py b/tests/sample_data.py
new file mode 100644
index 0000000..73487d1
--- /dev/null
+++ b/tests/sample_data.py
@@ -0,0 +1,15 @@
+from enum import Enum
+
+from pytket.circuit import Circuit
+from pytket.qasm.qasm import circuit_from_qasm
+
+
+class QasmFiles(Enum):
+    simple = 1
+    cond_1 = 2
+    bv_n10 = 3
+    baby = 4
+
+
+def get_qasm_as_circuit(qasm_file: QasmFiles) -> Circuit:
+    return circuit_from_qasm(f"tests/data/qasm/{qasm_file.name}.qasm")
diff --git a/tests/test_main.py b/tests/test_main.py
deleted file mode 100644
index 9d673cb..0000000
--- a/tests/test_main.py
+++ /dev/null
@@ -1,8 +0,0 @@
-"""Tests for pytket-phir.main module."""
-
-from pytket.phir.main import hello_world
-
-
-def test_hello_world():
-    """Test the hello_world function."""
-    assert hello_world() == "Hello, World!"
diff --git a/tests/test_sharder.py b/tests/test_sharder.py
new file mode 100644
index 0000000..7a6c533
--- /dev/null
+++ b/tests/test_sharder.py
@@ -0,0 +1,13 @@
+from pytket.phir.sharding.sharder import Sharder
+
+from .sample_data import QasmFiles, get_qasm_as_circuit
+
+
+class TestSharder:
+    def test_ctor(self) -> None:
+        sharder = Sharder(get_qasm_as_circuit(QasmFiles.baby))
+        assert sharder is not None
+
+        output = sharder.shard()
+
+        assert len(output) == 3
diff --git a/tests/test_utils.py b/tests/test_utils.py
deleted file mode 100644
index d181a80..0000000
--- a/tests/test_utils.py
+++ /dev/null
@@ -1,10 +0,0 @@
-"""Tests for pytket-phir.utils."""
-
-from pytket.phir.utils import add_numbers
-
-
-def test_add():
-    """Test the add function."""
-    assert add_numbers(2, 3) == 5  # noqa: PLR2004
-    assert add_numbers(0, 0) == 0
-    assert add_numbers(-1, 1) == 0