diff --git a/2023/Justfile b/2023/Justfile
new file mode 100644
index 0000000..fe6664c
--- /dev/null
+++ b/2023/Justfile
@@ -0,0 +1,12 @@
+
+# check
+default: check
+
+# show this help (just --list)
+help:
+    just --list
+
+# lint and run tests
+check:
+    poetry run black . --check
+    poetry run pytest
diff --git a/2023/day01.py b/2023/day01.py
new file mode 100644
index 0000000..414b008
--- /dev/null
+++ b/2023/day01.py
@@ -0,0 +1,61 @@
+#!/usr/bin/env python3
+
+from typing import TextIO
+import re
+
+# Part 2: Overlaps
+a = {
+    "one": "o1e",
+    "two": "t2o",
+    "three": "t3e",
+    "four": "f4r",
+    "five": "f5e",
+    "six": "s6x",
+    "seven": "s7n",
+    "eight": "e8t",
+    "nine": "n9e",
+    "ten": "t10e",
+}
+
+
+def calc(line: str) -> int:
+    e = re.findall(r"\d", line)
+
+    try:
+        first, *_, last = e
+    except ValueError:
+        first, last = e[0], e[0]
+
+    return int("".join([first, last]))
+
+
+def part1(f: TextIO) -> int:
+    values: int = 0
+
+    for line in f:
+        line = line.strip()
+
+        values += calc(line)
+
+    return values
+
+
+def part2(f: TextIO) -> int:
+    values: int = 0
+
+    for line in f:
+        line = line.strip()
+
+        for w, r in a.items():
+            line = line.replace(w, r)
+
+        values += calc(line)
+
+    return values
+
+
+if __name__ == "__main__":
+    with open("day01.txt") as f:
+        print(part1(f))
+    with open("day01.txt") as f:
+        print(part2(f))
diff --git a/2023/day01_test.py b/2023/day01_test.py
new file mode 100644
index 0000000..0cb4022
--- /dev/null
+++ b/2023/day01_test.py
@@ -0,0 +1,13 @@
+#!/usr/bin/env python3
+
+from day01 import *
+
+
+def test_part1() -> None:
+    with open("day01.txt") as p:
+        assert part1(p) == 54601
+
+
+def test_part2() -> None:
+    with open("day01.txt") as p:
+        assert part2(p) == 54078
diff --git a/2023/pyproject.toml b/2023/pyproject.toml
new file mode 100644
index 0000000..ba8fdc4
--- /dev/null
+++ b/2023/pyproject.toml
@@ -0,0 +1,15 @@
+[tool.poetry]
+name = "2023"
+version = "0.1.0"
+description = ""
+authors = ["Your Name <you@example.com>"]
+readme = "README.md"
+
+[tool.poetry.dependencies]
+python = "^3.11"
+pytest = "^7.4.3"
+
+
+[build-system]
+requires = ["poetry-core"]
+build-backend = "poetry.core.masonry.api"