diff --git a/exercises/diamond/canonical-data.json b/exercises/diamond/canonical-data.json
new file mode 100644
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+++ b/exercises/diamond/canonical-data.json
@@ -0,0 +1,125 @@
+{
+    "exercise": "diamond",
+    "version": "1.0.0",
+    "comments": [
+        " The tests contained within this canonical data file are suitable   ",
+        " for value-based testing, in which each test case checks that the   ",
+        " value returned by the function under test is in every way          ",
+        " identical to a given expected value.                               ",
+        "                                                                    ",
+        " This exercise is also amenable to property-based testing, in which ",
+        " each test case verifies that the value returned by the function    ",
+        " under test exhibits a specific desired property.                   ",
+        "                                                                    ",
+        " Several tracks (notably, C# and Go) forgo the value-based tests    ",
+        " below in favor of property-based tests. If you are feeling         ",
+        " adventurous and would like to use this exercise to introduce the   ",
+        " concept of property-based testing to participants in your track,   ",
+        " please ignore the value-based tests below and instead reference    ",
+        " the test suites in the aforementioned tracks.                      "
+    ],
+    "cases": [
+        {
+            "description": "Degenerate case with a single 'A' row",
+            "property": "rows",
+            "input": "A",
+            "expected": [
+                "A"
+            ]
+        },
+        {
+            "description": "Degenerate case with no row containing 3 distinct groups of spaces",
+            "property": "rows",
+            "input": "B",
+            "expected": [
+                " A ",
+                "B B",
+                " A "
+            ]
+        },
+        {
+            "description": "Smallest non-degenerate case with odd diamond side length",
+            "property": "rows",
+            "input": "C",
+            "expected": [
+                "  A  ",
+                " B B ",
+                "C   C",
+                " B B ",
+                "  A  "
+            ]
+        },
+        {
+            "description": "Smallest non-degenerate case with even diamond side length",
+            "property": "rows",
+            "input": "D",
+            "expected": [
+                "   A   ",
+                "  B B  ",
+                " C   C ",
+                "D     D",
+                " C   C ",
+                "  B B  ",
+                "   A   "
+            ]
+        },
+        {
+            "description": "Largest possible diamond",
+            "property": "rows",
+            "input": "Z",
+            "expected": [
+                "                         A                         ",
+                "                        B B                        ",
+                "                       C   C                       ",
+                "                      D     D                      ",
+                "                     E       E                     ",
+                "                    F         F                    ",
+                "                   G           G                   ",
+                "                  H             H                  ",
+                "                 I               I                 ",
+                "                J                 J                ",
+                "               K                   K               ",
+                "              L                     L              ",
+                "             M                       M             ",
+                "            N                         N            ",
+                "           O                           O           ",
+                "          P                             P          ",
+                "         Q                               Q         ",
+                "        R                                 R        ",
+                "       S                                   S       ",
+                "      T                                     T      ",
+                "     U                                       U     ",
+                "    V                                         V    ",
+                "   W                                           W   ",
+                "  X                                             X  ",
+                " Y                                               Y ",
+                "Z                                                 Z",
+                " Y                                               Y ",
+                "  X                                             X  ",
+                "   W                                           W   ",
+                "    V                                         V    ",
+                "     U                                       U     ",
+                "      T                                     T      ",
+                "       S                                   S       ",
+                "        R                                 R        ",
+                "         Q                               Q         ",
+                "          P                             P          ",
+                "           O                           O           ",
+                "            N                         N            ",
+                "             M                       M             ",
+                "              L                     L              ",
+                "               K                   K               ",
+                "                J                 J                ",
+                "                 I               I                 ",
+                "                  H             H                  ",
+                "                   G           G                   ",
+                "                    F         F                    ",
+                "                     E       E                     ",
+                "                      D     D                      ",
+                "                       C   C                       ",
+                "                        B B                        ",
+                "                         A                         "
+            ]
+        }
+    ]
+}
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