diff --git a/config.json b/config.json
index e1a56d6..0af6623 100644
--- a/config.json
+++ b/config.json
@@ -528,6 +528,14 @@
         "prerequisites": [],
         "difficulty": 3
       },
+      {
+        "slug": "state-of-tic-tac-toe",
+        "name": "State of Tic-Tac-Toe",
+        "uuid": "e5577ec3-ed40-418d-9da0-f932c4ef134e",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 2
+      },
       {
         "slug": "strain",
         "name": "Strain",
diff --git a/exercises/practice/state-of-tic-tac-toe/.docs/instructions.md b/exercises/practice/state-of-tic-tac-toe/.docs/instructions.md
new file mode 100644
index 0000000..1a03ebb
--- /dev/null
+++ b/exercises/practice/state-of-tic-tac-toe/.docs/instructions.md
@@ -0,0 +1,101 @@
+# Instructions
+
+In this exercise, you're going to implement a program that determines the state of a [tic-tac-toe][] game.
+(_You may also know the game as "noughts and crosses" or "Xs and Os"._)
+
+The game is played on a 3×3 grid.
+Players take turns to place `X`s and `O`s on the grid.
+The game ends when one player has won by placing three of marks in a row, column, or along a diagonal of the grid, or when the entire grid is filled up.
+
+In this exercise, we will assume that `X` starts.
+
+It's your job to determine which state a given game is in.
+
+There are 3 potential game states:
+
+- The game is **ongoing**.
+- The game ended in a **draw**.
+- The game ended in a **win**.
+
+If the given board is invalid, throw an appropriate error.
+
+If a board meets the following conditions, it is invalid:
+
+- The given board cannot be reached when turns are taken in the correct order (remember that `X` starts).
+- The game was played after it already ended.
+
+## Examples
+
+### Ongoing game
+
+```text
+   |   |
+ X |   |
+___|___|___
+   |   |
+   | X | O
+___|___|___
+   |   |
+ O | X |
+   |   |
+```
+
+### Draw
+
+```text
+   |   |
+ X | O | X
+___|___|___
+   |   |
+ X | X | O
+___|___|___
+   |   |
+ O | X | O
+   |   |
+```
+
+### Win
+
+```text
+   |   |
+ X | X | X
+___|___|___
+   |   |
+   | O | O
+___|___|___
+   |   |
+   |   |
+   |   |
+```
+
+### Invalid
+
+#### Wrong turn order
+
+```text
+   |   |
+ O | O | X
+___|___|___
+   |   |
+   |   |
+___|___|___
+   |   |
+   |   |
+   |   |
+```
+
+#### Continued playing after win
+
+```text
+   |   |
+ X | X | X
+___|___|___
+   |   |
+ O | O | O
+___|___|___
+   |   |
+   |   |
+   |   |
+```
+
+[tic-tac-toe]: https://en.wikipedia.org/wiki/Tic-tac-toe
diff --git a/exercises/practice/state-of-tic-tac-toe/.meta/config.json b/exercises/practice/state-of-tic-tac-toe/.meta/config.json
new file mode 100644
index 0000000..7538f5b
--- /dev/null
+++ b/exercises/practice/state-of-tic-tac-toe/.meta/config.json
@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "BNAndras"
+  ],
+  "files": {
+    "solution": [
+      "state_of_tic_tac_toe.vim"
+    ],
+    "test": [
+      "state_of_tic_tac_toe.vader"
+    ],
+    "example": [
+      ".meta/example.vim"
+    ]
+  },
+  "blurb": "Determine the game state of a match of Tic-Tac-Toe.",
+  "source": "Created by Sascha Mann for the Julia track of the Exercism Research Experiment.",
+  "source_url": "https://github.com/exercism/research_experiment_1/tree/julia-dev/exercises/julia-1-a"
+}
diff --git a/exercises/practice/state-of-tic-tac-toe/.meta/example.vim b/exercises/practice/state-of-tic-tac-toe/.meta/example.vim
new file mode 100644
index 0000000..64cc5b1
--- /dev/null
+++ b/exercises/practice/state-of-tic-tac-toe/.meta/example.vim
@@ -0,0 +1,93 @@
+" Determine the state of a Tic-Tac-Toe game represented
+" by a list of strings representing each row. An exception
+" is thrown if the board represents an invalid state.
+"
+function! Gamestate(board) abort
+  let x_count = 0
+  let o_count = 0
+
+  for row in a:board
+    let x_count += count(split(row, '\zs'), 'X')
+    let o_count += count(split(row, '\zs'), 'O')
+  endfor
+
+  if o_count > x_count
+    throw 'Wrong turn order: O started'
+  endif
+  if x_count > o_count + 1
+    throw 'Wrong turn order: X went twice'
+  endif
+
+  let x_won = s:CheckWin(a:board, 'X')
+  let o_won = s:CheckWin(a:board, 'O')
+
+  if x_won && o_won
+    throw 'Impossible board: game should have ended after the game was won'
+  endif
+
+  if x_won
+    if x_count == o_count
+      throw 'Impossible board: game should have ended after the game was won'
+    endif
+    return 'win'
+  endif
+
+  if o_won
+    if x_count > o_count
+      throw 'Impossible board: game should have ended after the game was won'
+    endif
+    return 'win'
+  endif
+
+  if x_count + o_count == 9
+    return 'draw'
+  endif
+
+  return 'ongoing'
+endfunction
+
+function! s:CheckWin(board, player) abort
+  " Three in a row
+  for row in a:board
+    if row ==# repeat(a:player, 3)
+      return v:true
+    endif
+  endfor
+
+  " Three in a column
+  for col in range(3)
+    let matches = 0
+    for row in range(3)
+      if a:board[row][col] ==# a:player
+        let matches += 1
+      endif
+    endfor
+    if matches == 3
+      return v:true
+    endif
+  endfor
+
+  " Diagonal from top-left to bottom-right
+  let matches = 0
+  for i in range(3)
+    if a:board[i][i] ==# a:player
+      let matches += 1
+    endif
+  endfor
+  if matches == 3
+    return v:true
+  endif
+
+  " Diagonal from top-right to bottom-left
+  let matches = 0
+  for i in range(3)
+    if a:board[i][2-i] ==# a:player
+      let matches += 1
+    endif
+  endfor
+  if matches == 3
+    return v:true
+  endif
+
+  return v:false
+endfunction
diff --git a/exercises/practice/state-of-tic-tac-toe/.meta/tests.toml b/exercises/practice/state-of-tic-tac-toe/.meta/tests.toml
new file mode 100644
index 0000000..8fc25e2
--- /dev/null
+++ b/exercises/practice/state-of-tic-tac-toe/.meta/tests.toml
@@ -0,0 +1,101 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[fe8e9fa9-37af-4d7e-aa24-2f4b8517161a]
+description = "Won games -> Finished game where X won via left column victory"
+
+[96c30df5-ae23-4cf6-bf09-5ef056dddea1]
+description = "Won games -> Finished game where X won via middle column victory"
+
+[0d7a4b0a-2afd-4a75-8389-5fb88ab05eda]
+description = "Won games -> Finished game where X won via right column victory"
+
+[bd1007c0-ec5d-4c60-bb9f-1a4f22177d51]
+description = "Won games -> Finished game where O won via left column victory"
+
+[c032f800-5735-4354-b1b9-46f14d4ee955]
+description = "Won games -> Finished game where O won via middle column victory"
+
+[662c8902-c94a-4c4c-9d9c-e8ca513db2b4]
+description = "Won games -> Finished game where O won via right column victory"
+
+[2d62121f-7e3a-44a0-9032-0d73e3494941]
+description = "Won games -> Finished game where X won via top row victory"
+
+[108a5e82-cc61-409f-aece-d7a18c1beceb]
+description = "Won games -> Finished game where X won via middle row victory"
+include = false
+
+[346527db-4db9-4a96-b262-d7023dc022b0]
+description = "Won games -> Finished game where X won via middle row victory"
+reimplements = "108a5e82-cc61-409f-aece-d7a18c1beceb"
+
+[a013c583-75f8-4ab2-8d68-57688ff04574]
+description = "Won games -> Finished game where X won via bottom row victory"
+
+[2c08e7d7-7d00-487f-9442-e7398c8f1727]
+description = "Won games -> Finished game where O won via top row victory"
+
+[bb1d6c62-3e3f-4d1a-9766-f8803c8ed70f]
+description = "Won games -> Finished game where O won via middle row victory"
+
+[6ef641e9-12ec-44f5-a21c-660ea93907af]
+description = "Won games -> Finished game where O won via bottom row victory"
+
+[ab145b7b-26a7-426c-ab71-bf418cd07f81]
+description = "Won games -> Finished game where X won via falling diagonal victory"
+
+[7450caab-08f5-4f03-a74b-99b98c4b7a4b]
+description = "Won games -> Finished game where X won via rising diagonal victory"
+
+[c2a652ee-2f93-48aa-a710-a70cd2edce61]
+description = "Won games -> Finished game where O won via falling diagonal victory"
+
+[5b20ceea-494d-4f0c-a986-b99efc163bcf]
+description = "Won games -> Finished game where O won via rising diagonal victory"
+
+[035a49b9-dc35-47d3-9d7c-de197161b9d4]
+description = "Won games -> Finished game where X won via a row and a column victory"
+
+[e5dfdeb0-d2bf-4b5a-b307-e673f69d4a53]
+description = "Won games -> Finished game where X won via two diagonal victories"
+
+[b42ed767-194c-4364-b36e-efbfb3de8788]
+description = "Drawn games -> Draw"
+
+[227a76b2-0fef-4e16-a4bd-8f9d7e4c3b13]
+description = "Drawn games -> Another draw"
+
+[4d93f15c-0c40-43d6-b966-418b040012a9]
+description = "Ongoing games -> Ongoing game: one move in"
+
+[c407ae32-4c44-4989-b124-2890cf531f19]
+description = "Ongoing games -> Ongoing game: two moves in"
+
+[199b7a8d-e2b6-4526-a85e-78b416e7a8a9]
+description = "Ongoing games -> Ongoing game: five moves in"
+
+[1670145b-1e3d-4269-a7eb-53cd327b302e]
+description = "Invalid boards -> Invalid board: X went twice"
+
+[47c048e8-b404-4bcf-9e51-8acbb3253f3b]
+description = "Invalid boards -> Invalid board: O started"
+
+[b1dc8b13-46c4-47db-a96d-aa90eedc4e8d]
+description = "Invalid boards -> Invalid board"
+include = false
+
+[6c1920f2-ab5c-4648-a0c9-997414dda5eb]
+description = "Invalid boards -> Invalid board: X won and O kept playing"
+reimplements = "b1dc8b13-46c4-47db-a96d-aa90eedc4e8d"
+
+[4801cda2-f5b7-4c36-8317-3cdd167ac22c]
+description = "Invalid boards -> Invalid board: players kept playing after a win"
diff --git a/exercises/practice/state-of-tic-tac-toe/state_of_tic_tac_toe.vader b/exercises/practice/state-of-tic-tac-toe/state_of_tic_tac_toe.vader
new file mode 100644
index 0000000..d5a5aae
--- /dev/null
+++ b/exercises/practice/state-of-tic-tac-toe/state_of_tic_tac_toe.vader
@@ -0,0 +1,138 @@
+Execute (Finished game where X won via left column victory):
+  let g:board = ['XOO', 'X  ', 'X  ']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where X won via middle column victory):
+  let g:board = ['OXO', ' X ', ' X ']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where X won via right column victory):
+  let g:board = ['OOX', '  X', '  X']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where O won via left column victory):
+  let g:board = ['OXX', 'OX ', 'O  ']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where O won via middle column victory):
+  let g:board = ['XOX', ' OX', ' O ']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where O won via right column victory):
+  let g:board = ['XXO', ' XO', '  O']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where X won via top row victory):
+  let g:board = ['XXX', 'XOO', 'O  ']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where X won via middle row victory):
+  let g:board = ['O  ', 'XXX', ' O ']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where X won via bottom row victory):
+  let g:board = [' OO', 'O X', 'XXX']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where O won via top row victory):
+  let g:board = ['OOO', 'XXO', 'XX ']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where O won via middle row victory):
+  let g:board = ['XX ', 'OOO', 'X  ']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where O won via bottom row victory):
+  let g:board = ['XOX', ' XX', 'OOO']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where X won via falling diagonal victory):
+  let g:board = ['XOO', ' X ', '  X']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where X won via rising diagonal victory):
+  let g:board = ['O X', 'OX ', 'X  ']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where O won via falling diagonal victory):
+  let g:board = ['OXX', 'OOX', 'X O']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where O won via rising diagonal victory):
+  let g:board = ['  O', ' OX', 'OXX']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where X won via a row and a column victory):
+  let g:board = ['XXX', 'XOO', 'XOO']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Finished game where X won via two diagonal victories):
+  let g:board = ['XOX', 'OXO', 'XOX']
+  let g:expected = 'win'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Draw):
+  let g:board = ['XOX', 'XXO', 'OXO']
+  let g:expected = 'draw'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Another draw):
+  let g:board = ['XXO', 'OXX', 'XOO']
+  let g:expected = 'draw'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Ongoing game: one move in):
+  let g:board = ['   ', 'X  ', '   ']
+  let g:expected = 'ongoing'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Ongoing game: two moves in):
+  let g:board = ['O  ', ' X ', '   ']
+  let g:expected = 'ongoing'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Ongoing game: five moves in):
+  let g:board = ['X  ', ' XO', 'OX ']
+  let g:expected = 'ongoing'
+  AssertEqual g:expected, Gamestate(g:board)
+
+Execute (Invalid board: X went twice):
+  let g:board = ['XX ', '   ', '   ']
+  let g:expected = 'Wrong turn order: X went twice'
+  AssertThrows call Gamestate(g:board)
+  AssertEqual g:expected, g:vader_exception
+
+Execute (Invalid board: O started):
+  let g:board = ['OOX', '   ', '   ']
+  let g:expected = 'Wrong turn order: O started'
+  AssertThrows call Gamestate(g:board)
+  AssertEqual g:expected, g:vader_exception
+
+Execute (Invalid board: X won and O kept playing):
+  let g:board = ['XXX', 'OOO', '   ']
+  let g:expected = 'Impossible board: game should have ended after the game was won'
+  AssertThrows call Gamestate(g:board)
+  AssertEqual g:expected, g:vader_exception
+
+Execute (Invalid board: players kept playing after a win):
+  let g:board = ['XXX', 'OOO', 'XOX']
+  let g:expected = 'Impossible board: game should have ended after the game was won'
+  AssertThrows call Gamestate(g:board)
+  AssertEqual g:expected, g:vader_exception
diff --git a/exercises/practice/state-of-tic-tac-toe/state_of_tic_tac_toe.vim b/exercises/practice/state-of-tic-tac-toe/state_of_tic_tac_toe.vim
new file mode 100644
index 0000000..64cc5b1
--- /dev/null
+++ b/exercises/practice/state-of-tic-tac-toe/state_of_tic_tac_toe.vim
@@ -0,0 +1,93 @@
+" Determine the state of a Tic-Tac-Toe game represented
+" by a list of strings representing each row. An exception
+" is thrown if the board represents an invalid state.
+"
+function! Gamestate(board) abort
+  let x_count = 0
+  let o_count = 0
+
+  for row in a:board
+    let x_count += count(split(row, '\zs'), 'X')
+    let o_count += count(split(row, '\zs'), 'O')
+  endfor
+
+  if o_count > x_count
+    throw 'Wrong turn order: O started'
+  endif
+  if x_count > o_count + 1
+    throw 'Wrong turn order: X went twice'
+  endif
+
+  let x_won = s:CheckWin(a:board, 'X')
+  let o_won = s:CheckWin(a:board, 'O')
+
+  if x_won && o_won
+    throw 'Impossible board: game should have ended after the game was won'
+  endif
+
+  if x_won
+    if x_count == o_count
+      throw 'Impossible board: game should have ended after the game was won'
+    endif
+    return 'win'
+  endif
+
+  if o_won
+    if x_count > o_count
+      throw 'Impossible board: game should have ended after the game was won'
+    endif
+    return 'win'
+  endif
+
+  if x_count + o_count == 9
+    return 'draw'
+  endif
+
+  return 'ongoing'
+endfunction
+
+function! s:CheckWin(board, player) abort
+  " Three in a row
+  for row in a:board
+    if row ==# repeat(a:player, 3)
+      return v:true
+    endif
+  endfor
+
+  " Three in a column
+  for col in range(3)
+    let matches = 0
+    for row in range(3)
+      if a:board[row][col] ==# a:player
+        let matches += 1
+      endif
+    endfor
+    if matches == 3
+      return v:true
+    endif
+  endfor
+
+  " Diagonal from top-left to bottom-right
+  let matches = 0
+  for i in range(3)
+    if a:board[i][i] ==# a:player
+      let matches += 1
+    endif
+  endfor
+  if matches == 3
+    return v:true
+  endif
+
+  " Diagonal from top-right to bottom-left
+  let matches = 0
+  for i in range(3)
+    if a:board[i][2-i] ==# a:player
+      let matches += 1
+    endif
+  endfor
+  if matches == 3
+    return v:true
+  endif
+
+  return v:false
+endfunction