diff --git a/package.json b/package.json
index cf2a6be..77ca1b1 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "chessops",
-  "version": "0.8.1-pstrat3.1",
+  "version": "0.8.1-pstrat3.2",
   "description": "Chess and chess variant rules and operations",
   "keywords": [
     "chess",
diff --git a/src/compat.ts b/src/compat.ts
index cda5808..1c98d85 100644
--- a/src/compat.ts
+++ b/src/compat.ts
@@ -57,6 +57,7 @@ export function lichessVariantRules(
     | 'fromPosition'
     | 'kingOfTheHill'
     | 'threeCheck'
+    | 'fiveCheck'
     | 'atomic'
     | 'horde'
     | 'racingKings'
@@ -72,6 +73,8 @@ export function lichessVariantRules(
       return 'chess';
     case 'threeCheck':
       return '3check';
+    case 'fiveCheck':
+      return '5check';
     case 'kingOfTheHill':
       return 'kingofthehill';
     case 'racingKings':
diff --git a/src/fen.ts b/src/fen.ts
index 8711ebe..a4b2ff9 100644
--- a/src/fen.ts
+++ b/src/fen.ts
@@ -115,13 +115,13 @@ export function parseRemainingChecks(part: string): Result<RemainingChecks, FenE
   if (parts.length === 3 && parts[0] === '') {
     const white = parseSmallUint(parts[1]);
     const black = parseSmallUint(parts[2]);
-    if (!defined(white) || white > 3 || !defined(black) || black > 3)
+    if (!defined(white) || white > 5 || !defined(black) || black > 5)
       return Result.err(new FenError(InvalidFen.RemainingChecks));
-    return Result.ok(new RemainingChecks(3 - white, 3 - black));
+    return Result.ok(new RemainingChecks(5 - white, 5 - black)); //Old notation counting down, not used in games, therefore using highest check mode 5
   } else if (parts.length === 2) {
     const white = parseSmallUint(parts[0]);
     const black = parseSmallUint(parts[1]);
-    if (!defined(white) || white > 3 || !defined(black) || black > 3)
+    if (!defined(white) || white > 5 || !defined(black) || black > 5)
       return Result.err(new FenError(InvalidFen.RemainingChecks));
     return Result.ok(new RemainingChecks(white, black));
   } else return Result.err(new FenError(InvalidFen.RemainingChecks));
diff --git a/src/setup.ts b/src/setup.ts
index dabff85..5955aaa 100644
--- a/src/setup.ts
+++ b/src/setup.ts
@@ -174,6 +174,10 @@ export class RemainingChecks {
     return new RemainingChecks(3, 3);
   }
 
+  static fiveCheck(): RemainingChecks {
+    return new RemainingChecks(5, 5);
+  }
+
   clone(): RemainingChecks {
     return new RemainingChecks(this.white, this.black);
   }
diff --git a/src/types.ts b/src/types.ts
index 63b94cd..4e53c1e 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -111,6 +111,7 @@ export const RULES = [
   'antichess',
   'kingofthehill',
   '3check',
+  '5check',
   'atomic',
   'horde',
   'racingkings',
diff --git a/src/variant.ts b/src/variant.ts
index 5d35ee5..555bec3 100644
--- a/src/variant.ts
+++ b/src/variant.ts
@@ -346,6 +346,46 @@ export class ThreeCheck extends Chess {
   }
 }
 
+export class FiveCheck extends Chess {
+  protected constructor() {
+    super('5check');
+  }
+
+  static default(): FiveCheck {
+    const pos = super.default();
+    pos.remainingChecks = RemainingChecks.fiveCheck();
+    return pos;
+  }
+
+  static fromSetup(setup: Setup): Result<FiveCheck, PositionError> {
+    return super.fromSetup(setup).map(pos => {
+      pos.remainingChecks = setup.remainingChecks ? setup.remainingChecks.clone() : RemainingChecks.fiveCheck();
+      return pos;
+    });
+  }
+
+  clone(): FiveCheck {
+    return super.clone() as FiveCheck;
+  }
+
+  hasInsufficientMaterial(color: Color): boolean {
+    return this.board.pieces(color, 'k-piece').equals(this.board[color]);
+  }
+
+  isVariantEnd(): boolean {
+    return !!this.remainingChecks && (this.remainingChecks.white <= 0 || this.remainingChecks.black <= 0);
+  }
+
+  variantOutcome(_ctx?: Context): Outcome | undefined {
+    if (this.remainingChecks) {
+      for (const color of COLORS) {
+        if (this.remainingChecks[color] <= 0) return { winner: color };
+      }
+    }
+    return;
+  }
+}
+
 class RacingKings extends Chess {
   protected constructor() {
     super('racingkings');
@@ -618,6 +658,8 @@ export function defaultPosition(rules: Rules): Position {
       return KingOfTheHill.default();
     case '3check':
       return ThreeCheck.default();
+    case '5check':
+      return FiveCheck.default();
     case 'crazyhouse':
       return Crazyhouse.default();
     case 'linesofaction':
@@ -645,6 +687,8 @@ export function setupPosition(rules: Rules, setup: Setup): Result<Position, Posi
       return KingOfTheHill.fromSetup(setup);
     case '3check':
       return ThreeCheck.fromSetup(setup);
+    case '5check':
+      return FiveCheck.fromSetup(setup);
     case 'crazyhouse':
       return Crazyhouse.fromSetup(setup);
     case 'linesofaction':
diff --git a/test/variant.test.ts b/test/variant.test.ts
index 5bbcb18..eb96f8e 100644
--- a/test/variant.test.ts
+++ b/test/variant.test.ts
@@ -70,6 +70,9 @@ const insufficientMaterial: [Rules, string, boolean, boolean][] = [
   ['3check', '8/5k2/8/8/8/8/3K4/8 w - - 3+3', true, true],
   ['3check', '8/5k2/8/8/8/8/3K2N1/8 w - - 3+3', false, true],
 
+  ['5check', '8/5k2/8/8/8/8/3K4/8 w - - 5+5', true, true],
+  ['5check', '8/5k2/8/8/8/8/3K2N1/8 w - - 5+5', false, true],
+
   ['crazyhouse', '8/5k2/8/8/8/8/3K2N1/8[] w - -', true, true],
   ['crazyhouse', '8/5k2/8/8/8/5B2/3KB3/8[] w - -', false, false],