diff --git a/Cargo.lock b/Cargo.lock
index 93efbef..4118f22 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2503,6 +2503,16 @@ dependencies = [
  "version_check 0.9.4",
 ]
 
+[[package]]
+name = "nary_tree"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fb86edb8951cb3852cbb33ef558650e9f18c9d2e7fd79a6849c984a3825719c7"
+dependencies = [
+ "slab",
+ "snowflake",
+]
+
 [[package]]
 name = "native-tls"
 version = "0.2.11"
@@ -2705,10 +2715,10 @@ dependencies = [
  "config-derive",
  "cool_asserts",
  "grid",
+ "nary_tree",
  "serde 1.0.193",
  "serde_json",
  "sgf",
- "slab_tree",
  "thiserror",
  "uuid 0.8.2",
 ]
@@ -3686,9 +3696,9 @@ version = "0.1.0"
 dependencies = [
  "chrono",
  "cool_asserts",
+ "nary_tree",
  "nom",
  "serde 1.0.193",
- "slab_tree",
  "thiserror",
  "typeshare",
  "uuid 0.8.2",
@@ -3762,15 +3772,6 @@ dependencies = [
  "autocfg 1.1.0",
 ]
 
-[[package]]
-name = "slab_tree"
-version = "0.3.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "f9e8b45abe77b7cab703054a11973cffe164c82c5ff5e211ae5a73af5e42e39f"
-dependencies = [
- "snowflake",
-]
-
 [[package]]
 name = "smallvec"
 version = "1.11.2"
diff --git a/otg/core/Cargo.toml b/otg/core/Cargo.toml
index a6b7215..42af9aa 100644
--- a/otg/core/Cargo.toml
+++ b/otg/core/Cargo.toml
@@ -14,7 +14,7 @@ sgf             = { path = "../../sgf" }
 grid            = { version = "0.9" }
 serde_json      = { version = "1" }
 serde           = { version = "1", features = [ "derive" ] }
-slab_tree   = { version = "0.3" }
+nary_tree       = { version = "0.4" }
 thiserror       = { version = "1" }
 uuid            = { version = "0.8", features = ["v4", "serde"] }
 
diff --git a/otg/core/src/types.rs b/otg/core/src/types.rs
index c48cc7f..7ce672b 100644
--- a/otg/core/src/types.rs
+++ b/otg/core/src/types.rs
@@ -242,10 +242,10 @@ pub struct Tree<T> {
 }
 */
 
-pub struct DepthTree(slab_tree::Tree<SizeNode>);
+pub struct DepthTree(nary_tree::Tree<SizeNode>);
 
 impl Deref for DepthTree {
-    type Target = slab_tree::Tree<SizeNode>;
+    type Target = nary_tree::Tree<SizeNode>;
 
     fn deref(&self) -> &Self::Target {
         &self.0
@@ -254,8 +254,8 @@ impl Deref for DepthTree {
 
 #[derive(Debug)]
 pub struct SizeNode {
-    node_id: slab_tree::NodeId,
-    parent: Option<slab_tree::NodeId>,
+    node_id: nary_tree::NodeId,
+    parent: Option<nary_tree::NodeId>,
     depth: usize,
     width: usize,
 }
@@ -275,7 +275,7 @@ impl DepthTree {
     // so I want to eliminate the "Tree" above and keep using the slab tree. I think I should be able
     // to build these Node objects without needing a custom data structure.
     fn new() -> Self {
-        Self(slab_tree::Tree::new())
+        Self(nary_tree::Tree::new())
         /*
         Tree {
             nodes: vec![Node {
@@ -415,8 +415,8 @@ impl<'a> From<&'a GameTree> for DepthTree {
                 // The id_map indexes from the source tree to the destination tree. Reverse
                 // indexing is accomplished by looking at the node_id in a node in the destination
                 // tree.
-                let mut id_map: HashMap<slab_tree::NodeId, slab_tree::NodeId> = HashMap::new();
-                let mut tree = slab_tree::Tree::new();
+                let mut id_map: HashMap<nary_tree::NodeId, nary_tree::NodeId> = HashMap::new();
+                let mut tree = nary_tree::Tree::new();
 
                 let mut iter = source_root_node.traverse_pre_order();
                 let _ = iter.next().unwrap(); // we already know that the first element to be
@@ -522,7 +522,7 @@ impl<'a> From<&'a GameNode> for Tree<Uuid> {
 
 pub struct BFSIter<'a, T> {
     tree: &'a DepthTree,
-    queue: VecDeque<slab_tree::NodeRef<'a, T>>,
+    queue: VecDeque<nary_tree::NodeRef<'a, T>>,
 }
 
 impl<'a, T> Iterator for BFSIter<'a, T> {
diff --git a/sgf/Cargo.toml b/sgf/Cargo.toml
index b1fda71..0b83c35 100644
--- a/sgf/Cargo.toml
+++ b/sgf/Cargo.toml
@@ -9,7 +9,7 @@ edition = "2021"
 chrono      = { version = "0.4", features = [ "serde" ] }
 nom         = { version = "7" }
 serde       = { version = "1", features = [ "derive" ] }
-slab_tree   = { version = "0.3" }
+nary_tree   = { version = "0.4" }
 thiserror   = { version = "1"}
 typeshare   = { version = "1" }
 uuid        = { version = "0.8", features = ["v4", "serde"] }
diff --git a/sgf/src/game.rs b/sgf/src/game.rs
index ae11f54..d21812a 100644
--- a/sgf/src/game.rs
+++ b/sgf/src/game.rs
@@ -3,9 +3,10 @@ use crate::{
     Color, Date, GameResult, GameType,
 };
 use serde::{Deserialize, Serialize};
-use slab_tree::{NodeId, NodeMut, NodeRef, Tree};
+use nary_tree::{NodeId, NodeMut, NodeRef, Tree};
 use std::{
     collections::{HashMap, HashSet, VecDeque},
+    fmt,
     fmt::Debug,
     ops::{Deref, DerefMut},
     time::Duration,
@@ -425,6 +426,15 @@ pub enum GameNode {
     SetupNode(SetupNode),
 }
 
+impl fmt::Display for GameNode {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), fmt::Error> {
+        match self {
+            GameNode::MoveNode(_) => write!(f, "MoveNode"),
+            GameNode::SetupNode(_) => write!(f, "SetupNode"),
+        }
+    }
+}
+
 impl GameNode {
     pub fn id(&self) -> Uuid {
         match self {