diff --git a/Cargo.lock b/Cargo.lock
index bb74c16..7137afc 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -2304,6 +2304,7 @@ name = "sgf"
 version = "0.1.0"
 dependencies = [
  "chrono",
+ "cool_asserts",
  "nom",
  "serde",
  "thiserror",
diff --git a/sgf/Cargo.toml b/sgf/Cargo.toml
index ab75ce2..2dbd6bf 100644
--- a/sgf/Cargo.toml
+++ b/sgf/Cargo.toml
@@ -11,3 +11,6 @@ nom         = { version = "7" }
 serde       = { version = "1", features = [ "derive" ] }
 thiserror   = { version = "1"}
 typeshare   = { version = "1" }
+
+[dev-dependencies]
+cool_asserts    = { version = "2" }
diff --git a/sgf/src/go.rs b/sgf/src/go.rs
index 0fc3db0..ea6faa4 100644
--- a/sgf/src/go.rs
+++ b/sgf/src/go.rs
@@ -74,6 +74,7 @@ use crate::{
     Error,
 };
 use serde::{Deserialize, Serialize};
+use std::ops::Deref;
 use typeshare::typeshare;
 
 #[derive(Clone, Debug)]
@@ -84,11 +85,18 @@ pub struct Game {
     pub tree: Tree,
 }
 
+impl Deref for Game {
+    type Target = Tree;
+    fn deref(&self) -> &Self::Target {
+        &self.tree
+    }
+}
+
 impl TryFrom<Tree> for Game {
     type Error = Error;
 
     fn try_from(tree: Tree) -> Result<Self, Self::Error> {
-        let board_size = match tree.sequence[0].find_prop("SZ") {
+        let board_size = match tree.root.find_prop("SZ") {
             Some(prop) => Size::try_from(prop.values[0].as_str())?,
             None => Size {
                 width: 19,
@@ -108,28 +116,31 @@ impl TryFrom<Tree> for Game {
             .find_prop("PB")
             .map(|prop| prop.values.join(", "));
 
-        info.black_rank = tree.sequence[0]
+        info.black_rank = tree
+            .root
             .find_prop("BR")
             .and_then(|prop| Rank::try_from(prop.values[0].as_str()).ok());
 
-        info.white_player = tree.sequence[0]
-            .find_prop("PW")
-            .map(|prop| prop.values.join(", "));
+        info.white_player = tree.root.find_prop("PW").map(|prop| prop.values.join(", "));
 
-        info.white_rank = tree.sequence[0]
+        info.white_rank = tree
+            .root
             .find_prop("WR")
             .and_then(|prop| Rank::try_from(prop.values[0].as_str()).ok());
 
-        info.result = tree.sequence[0]
+        info.result = tree
+            .root
             .find_prop("RE")
             .and_then(|prop| GameResult::try_from(prop.values[0].as_str()).ok());
 
-        info.time_limits = tree.sequence[0]
+        info.time_limits = tree
+            .root
             .find_prop("TM")
             .and_then(|prop| prop.values[0].parse::<u64>().ok())
             .and_then(|seconds| Some(std::time::Duration::from_secs(seconds)));
 
-        info.date = tree.sequence[0]
+        info.date = tree
+            .root
             .find_prop("DT")
             .and_then(|prop| {
                 let v = prop
@@ -149,21 +160,13 @@ impl TryFrom<Tree> for Game {
             })
             .unwrap_or(vec![]);
 
-        info.event = tree.sequence[0]
-            .find_prop("EV")
-            .map(|prop| prop.values.join(", "));
+        info.event = tree.root.find_prop("EV").map(|prop| prop.values.join(", "));
 
-        info.round = tree.sequence[0]
-            .find_prop("RO")
-            .map(|prop| prop.values.join(", "));
+        info.round = tree.root.find_prop("RO").map(|prop| prop.values.join(", "));
 
-        info.source = tree.sequence[0]
-            .find_prop("SO")
-            .map(|prop| prop.values.join(", "));
+        info.source = tree.root.find_prop("SO").map(|prop| prop.values.join(", "));
 
-        info.game_keeper = tree.sequence[0]
-            .find_prop("US")
-            .map(|prop| prop.values.join(", "));
+        info.game_keeper = tree.root.find_prop("US").map(|prop| prop.values.join(", "));
 
         Ok(Game {
             board_size,
@@ -307,7 +310,7 @@ mod tests {
     use super::*;
     use crate::{
         date::Date,
-        tree::{parse_collection, Size},
+        tree::{parse_collection, Property, Size},
     };
     use std::fs::File;
     use std::io::Read;
@@ -390,4 +393,32 @@ mod tests {
             assert_eq!(tree.info.game_keeper, Some("Arno Hollosi".to_owned()));
         });
     }
+
+    #[test]
+    fn it_presents_a_mainline() {
+        with_file(
+            std::path::Path::new("test_data/2020 USGO DDK, Round 1.sgf"),
+            |trees| {
+                assert_eq!(trees.len(), 1);
+                let tree = &trees[0];
+
+                let node = &tree.root;
+                println!("{:?}", node);
+
+                let node = node.next();
+                println!("{:?}", node);
+
+                /*
+                assert_eq!(
+                    node.find_prop("B"),
+                    Some(Property {
+                        ident: "B".to_owned(),
+                        values: vec!["dp".to_owned()]
+                    })
+                );
+                */
+                assert!(false);
+            },
+        );
+    }
 }
diff --git a/sgf/src/lib.rs b/sgf/src/lib.rs
index 4b4f8fa..d30fa13 100644
--- a/sgf/src/lib.rs
+++ b/sgf/src/lib.rs
@@ -61,6 +61,7 @@ pub enum Game {
     Unsupported(tree::Tree),
 }
 
+/*
 pub fn parse_sgf(input: &str) -> Result<Vec<Game>, Error> {
     let (_, trees) = parse_collection::<nom::error::VerboseError<&str>>(input)?;
     Ok(trees
@@ -73,6 +74,7 @@ pub fn parse_sgf(input: &str) -> Result<Vec<Game>, Error> {
         })
         .collect::<Vec<Game>>())
 }
+*/
 
 /*
 impl From<(&str, VerboseErrorKind)> for
diff --git a/sgf/src/tree.rs b/sgf/src/tree.rs
index 59d24c0..1d9a804 100644
--- a/sgf/src/tree.rs
+++ b/sgf/src/tree.rs
@@ -54,29 +54,19 @@ impl TryFrom<&str> for Size {
 
 #[derive(Clone, Debug, PartialEq)]
 pub struct Tree {
-    pub sequence: Vec<Node>,
-    pub sub_sequences: Vec<Tree>,
+    pub root: Node,
 }
 
 impl ToString for Tree {
     fn to_string(&self) -> String {
-        let sequence = self
-            .sequence
-            .iter()
-            .map(|node| node.to_string())
-            .collect::<String>();
-        let subsequences = self
-            .sub_sequences
-            .iter()
-            .map(|seq| seq.to_string())
-            .collect::<String>();
-        format!("({}{})", sequence, subsequences)
+        format!("({})", self.root.to_string())
     }
 }
 
 #[derive(Clone, Debug, PartialEq)]
 pub struct Node {
     pub properties: Vec<Property>,
+    pub next: Vec<Node>,
 }
 
 impl ToString for Node {
@@ -86,7 +76,21 @@ impl ToString for Node {
             .iter()
             .map(|prop| prop.to_string())
             .collect::<String>();
-        format!(";{}", props)
+
+        let next = if self.next.len() == 1 {
+            self.next
+                .iter()
+                .map(|node| node.to_string())
+                .collect::<Vec<String>>()
+                .join("")
+        } else {
+            self.next
+                .iter()
+                .map(|node| format!("({})", node.to_string()))
+                .collect::<Vec<String>>()
+                .join("")
+        };
+        format!(";{}{}", props, next)
     }
 }
 
@@ -97,6 +101,10 @@ impl Node {
             .find(|prop| prop.ident == ident)
             .cloned()
     }
+
+    pub fn next<'a>(&'a self) -> Option<&'a Node> {
+        self.next.get(0)
+    }
 }
 
 #[derive(Clone, Debug, PartialEq)]
@@ -119,40 +127,40 @@ impl ToString for Property {
 pub fn parse_collection<'a, E: nom::error::ParseError<&'a str>>(
     input: &'a str,
 ) -> IResult<&'a str, Vec<Tree>, E> {
-    separated_list1(multispace1, parse_tree)(input)
+    let (input, roots) = separated_list1(multispace1, parse_tree)(input)?;
+    let trees = roots
+        .into_iter()
+        .map(|root| Tree { root })
+        .collect::<Vec<Tree>>();
+
+    Ok((input, trees))
 }
 
 // note: must preserve unknown properties
 // note: must fix or preserve illegally formatted game-info properties
 // note: must correct or delete illegally foramtted properties, but display a warning
-fn parse_tree<'a, E: nom::error::ParseError<&'a str>>(input: &'a str) -> IResult<&'a str, Tree, E> {
+fn parse_tree<'a, E: nom::error::ParseError<&'a str>>(input: &'a str) -> IResult<&'a str, Node, E> {
     let (input, _) = multispace0(input)?;
-    delimited(tag("("), parse_sequence, tag(")"))(input)
-}
+    let (input, _) = tag("(")(input)?;
+    let (input, node) = parse_node(input)?;
+    let (input, _) = multispace0(input)?;
+    let (input, _) = tag(")")(input)?;
 
-fn parse_sequence<'a, E: nom::error::ParseError<&'a str>>(
-    input: &'a str,
-) -> IResult<&'a str, Tree, E> {
-    let (input, _) = multispace0(input)?;
-    let (input, nodes) = many1(parse_node)(input)?;
-    let (input, _) = multispace0(input)?;
-    let (input, sub_sequences) = many0(parse_tree)(input)?;
-    let (input, _) = multispace0(input)?;
-
-    Ok((
-        input,
-        Tree {
-            sequence: nodes,
-            sub_sequences,
-        },
-    ))
+    Ok((input, node))
 }
 
 fn parse_node<'a, E: nom::error::ParseError<&'a str>>(input: &'a str) -> IResult<&'a str, Node, E> {
     let (input, _) = multispace0(input)?;
-    let (input, _) = tag(";")(input)?;
+    let (input, _) = opt(tag(";"))(input)?;
     let (input, properties) = many1(parse_property)(input)?;
-    Ok((input, Node { properties }))
+
+    let (input, next) = opt(parse_node)(input)?;
+    let (input, mut next_seq) = many0(parse_tree)(input)?;
+
+    let mut next = next.map(|n| vec![n]).unwrap_or(vec![]);
+    next.append(&mut next_seq);
+
+    Ok((input, Node { properties, next }))
 }
 
 fn parse_property<'a, E: nom::error::ParseError<&'a str>>(
@@ -219,9 +227,8 @@ pub fn parse_size<'a, E: nom::error::ParseError<&'a str>>(
 
 #[cfg(test)]
 mod test {
-    use std::{fs::File, io::Read};
-
     use super::*;
+    use cool_asserts::assert_matches;
 
     const EXAMPLE: &'static str = "(;FF[4]C[root](;C[a];C[b](;C[c])
 (;C[d];C[e]))
@@ -259,7 +266,8 @@ mod test {
                 properties: vec![Property {
                     ident: "B".to_owned(),
                     values: vec!["ab".to_owned()]
-                }]
+                }],
+                next: vec![]
             }
         );
 
@@ -273,6 +281,25 @@ mod test {
                 properties: vec![Property {
                     ident: "B".to_owned(),
                     values: vec!["ab".to_owned()]
+                }],
+                next: vec![Node {
+                    properties: vec![Property {
+                        ident: "W".to_owned(),
+                        values: vec!["dp".to_owned()]
+                    }],
+                    next: vec![Node {
+                        properties: vec![
+                            Property {
+                                ident: "B".to_owned(),
+                                values: vec!["pq".to_owned()]
+                            },
+                            Property {
+                                ident: "C".to_owned(),
+                                values: vec!["some comments".to_owned()]
+                            }
+                        ],
+                        next: vec![],
+                    }]
                 }]
             }
         );
@@ -286,21 +313,17 @@ mod test {
 
         assert_eq!(
             sequence,
-            Tree {
-                sequence: vec![
-                    Node {
-                        properties: vec![Property {
-                            ident: "B".to_owned(),
-                            values: vec!["ab".to_owned()]
-                        }]
-                    },
-                    Node {
-                        properties: vec![Property {
-                            ident: "W".to_owned(),
-                            values: vec!["dp".to_owned()]
-                        }]
-                    },
-                    Node {
+            Node {
+                properties: vec![Property {
+                    ident: "B".to_owned(),
+                    values: vec!["ab".to_owned()]
+                }],
+                next: vec![Node {
+                    properties: vec![Property {
+                        ident: "W".to_owned(),
+                        values: vec!["dp".to_owned()]
+                    }],
+                    next: vec![Node {
                         properties: vec![
                             Property {
                                 ident: "B".to_owned(),
@@ -310,114 +333,158 @@ mod test {
                                 ident: "C".to_owned(),
                                 values: vec!["some comments".to_owned()]
                             }
-                        ]
-                    }
-                ],
-                sub_sequences: vec![],
-            }
+                        ],
+                        next: vec![],
+                    }]
+                }],
+            },
         );
     }
 
     #[test]
-    fn it_can_parse_a_sequence_with_subsequences() {
+    fn it_can_parse_a_branching_sequence() {
         let text = "(;C[a];C[b](;C[c])(;C[d];C[e]))";
-        let (_, sequence) = parse_tree::<nom::error::VerboseError<&str>>(text).unwrap();
+        let (_, tree) = parse_tree::<nom::error::VerboseError<&str>>(text).unwrap();
 
-        let main_sequence = vec![
-            Node {
-                properties: vec![Property {
-                    ident: "C".to_owned(),
-                    values: vec!["a".to_owned()],
-                }],
-            },
-            Node {
+        let expected = Node {
+            properties: vec![Property {
+                ident: "C".to_owned(),
+                values: vec!["a".to_owned()],
+            }],
+            next: vec![Node {
                 properties: vec![Property {
                     ident: "C".to_owned(),
                     values: vec!["b".to_owned()],
                 }],
-            },
-        ];
-        let subsequence_1 = Tree {
-            sequence: vec![Node {
-                properties: vec![Property {
-                    ident: "C".to_owned(),
-                    values: vec!["c".to_owned()],
-                }],
+                next: vec![
+                    Node {
+                        properties: vec![Property {
+                            ident: "C".to_owned(),
+                            values: vec!["c".to_owned()],
+                        }],
+                        next: vec![],
+                    },
+                    Node {
+                        properties: vec![Property {
+                            ident: "C".to_owned(),
+                            values: vec!["d".to_owned()],
+                        }],
+                        next: vec![Node {
+                            properties: vec![Property {
+                                ident: "C".to_owned(),
+                                values: vec!["e".to_owned()],
+                            }],
+                            next: vec![],
+                        }],
+                    },
+                ],
             }],
-            sub_sequences: vec![],
-        };
-        let subsequence_2 = Tree {
-            sequence: vec![
-                Node {
-                    properties: vec![Property {
-                        ident: "C".to_owned(),
-                        values: vec!["d".to_owned()],
-                    }],
-                },
-                Node {
-                    properties: vec![Property {
-                        ident: "C".to_owned(),
-                        values: vec!["e".to_owned()],
-                    }],
-                },
-            ],
-            sub_sequences: vec![],
         };
 
-        assert_eq!(
-            sequence,
-            Tree {
-                sequence: main_sequence,
-                sub_sequences: vec![subsequence_1, subsequence_2],
-            }
-        );
+        assert_eq!(tree, expected);
     }
 
     #[test]
     fn it_can_parse_example_1() {
-        let (_, ex_tree) = parse_tree::<nom::error::VerboseError<&str>>(EXAMPLE).unwrap();
-        assert_eq!(ex_tree.sequence.len(), 1);
+        let (_, tree) = parse_tree::<nom::error::VerboseError<&str>>(EXAMPLE).unwrap();
 
-        assert_eq!(ex_tree.sequence[0].properties.len(), 2);
-        assert_eq!(
-            ex_tree.sequence[0].properties[0],
-            Property {
-                ident: "FF".to_owned(),
-                values: vec!["4".to_owned()]
-            }
-        );
-        assert_eq!(ex_tree.sub_sequences.len(), 2);
+        let j = Node {
+            properties: vec![Property {
+                ident: "C".to_owned(),
+                values: vec!["j".to_owned()],
+            }],
+            next: vec![],
+        };
+        let i = Node {
+            properties: vec![Property {
+                ident: "C".to_owned(),
+                values: vec!["i".to_owned()],
+            }],
+            next: vec![],
+        };
+        let h = Node {
+            properties: vec![Property {
+                ident: "C".to_owned(),
+                values: vec!["h".to_owned()],
+            }],
+            next: vec![i],
+        };
+        let g = Node {
+            properties: vec![Property {
+                ident: "C".to_owned(),
+                values: vec!["g".to_owned()],
+            }],
+            next: vec![h],
+        };
+        let f = Node {
+            properties: vec![Property {
+                ident: "C".to_owned(),
+                values: vec!["f".to_owned()],
+            }],
+            next: vec![g, j],
+        };
+        let e = Node {
+            properties: vec![Property {
+                ident: "C".to_owned(),
+                values: vec!["e".to_owned()],
+            }],
+            next: vec![],
+        };
+        let d = Node {
+            properties: vec![Property {
+                ident: "C".to_owned(),
+                values: vec!["d".to_owned()],
+            }],
+            next: vec![e],
+        };
+        let c = Node {
+            properties: vec![Property {
+                ident: "C".to_owned(),
+                values: vec!["c".to_owned()],
+            }],
+            next: vec![],
+        };
+        let b = Node {
+            properties: vec![Property {
+                ident: "C".to_owned(),
+                values: vec!["b".to_owned()],
+            }],
+            next: vec![c, d],
+        };
+        let a = Node {
+            properties: vec![Property {
+                ident: "C".to_owned(),
+                values: vec!["a".to_owned()],
+            }],
+            next: vec![b],
+        };
+        let expected = Node {
+            properties: vec![
+                Property {
+                    ident: "FF".to_owned(),
+                    values: vec!["4".to_owned()],
+                },
+                Property {
+                    ident: "C".to_owned(),
+                    values: vec!["root".to_owned()],
+                },
+            ],
+            next: vec![a, f],
+        };
 
-        assert_eq!(ex_tree.sub_sequences[0].sequence.len(), 2);
-        assert_eq!(
-            ex_tree.sub_sequences[0].sequence,
-            vec![
-                Node {
-                    properties: vec![Property {
-                        ident: "C".to_owned(),
-                        values: vec!["a".to_owned()]
-                    }]
-                },
-                Node {
-                    properties: vec![Property {
-                        ident: "C".to_owned(),
-                        values: vec!["b".to_owned()]
-                    }]
-                },
-            ]
-        );
-        assert_eq!(ex_tree.sub_sequences[0].sub_sequences.len(), 2);
+        assert_eq!(tree, expected);
     }
 
     #[test]
     fn it_can_regenerate_the_tree() {
         let (_, tree1) = parse_tree::<nom::error::VerboseError<&str>>(EXAMPLE).unwrap();
+        let tree1 = Tree { root: tree1 };
         assert_eq!(
             tree1.to_string(),
             "(;FF[4]C[root](;C[a];C[b](;C[c])(;C[d];C[e]))(;C[f](;C[g];C[h];C[i])(;C[j])))"
         );
         let (_, tree2) = parse_tree::<nom::error::VerboseError<&str>>(&tree1.to_string()).unwrap();
-        assert_eq!(tree1, tree2);
+        assert_eq!(tree1, Tree { root: tree2 });
     }
 
     #[test]