diff --git a/2021/inputs/day21 b/2021/inputs/day21
new file mode 100644
index 0000000..5ad5c4a
--- /dev/null
+++ b/2021/inputs/day21
@@ -0,0 +1,2 @@
+Player 1 starting position: 7
+Player 2 starting position: 3
diff --git a/2021/src/bin/day21.rs b/2021/src/bin/day21.rs
new file mode 100644
index 0000000..4c8328c
--- /dev/null
+++ b/2021/src/bin/day21.rs
@@ -0,0 +1,38 @@
+#![feature(test)]
+extern crate test;
+use aoc2021::common::*;
+
+const DAY: usize = 21;
+type Parsed = Vec<usize>;
+
+fn parse_input(raw: &str) -> Parsed {
+    unimplemented!()
+}
+
+fn part1(parsed: &Parsed) -> usize {
+    unimplemented!()
+}
+
+fn part2(parsed: &Parsed) -> usize {
+    unimplemented!()
+}
+
+fn main() {
+    let input = parse_input(&read_file(DAY));
+    println!("Part 1: {}", part1(&input));
+    println!("Part 2: {}", part2(&input));
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use aoc2021::*;
+
+    const TEST_INPUT: &str = "";
+
+    test!(part1() == 0);
+    test!(part2() == 0);
+    bench!(part1() == 0);
+    bench!(part2() == 0);
+    bench_input!(Vec::len => 0);
+}