yes

Sources/Engine/Board.swift

@@ -76,6 +76,12 @@ public class Board: CustomStringConvertible, EventDelegate {
 
 	func notify(_ event: Event) {
 		#warning("Not implemented")
+		switch event {
+		case .kingInCheck(let piece, let king):
+			king.insertThreat(piece)
+		case .piecePinned(let p1, let p2):
+			break
+		}
 	}
 
 	internal func addPieceToTarget(_ piece: Piece, target: Square.Position) {

Sources/Engine/Pieces/Bishop.swift

@@ -29,13 +29,16 @@ final class Bishop: Piece, DiagonalMoves {
 						if let king = piece as? King {
 							delegate?.notify(.kingInCheck(self, on: king))
 							legalPositions.removeLast()
+							last = position
+							return
 						} else {
 							delegate?.notify(
 								.piecePinned(from: self, on: piece))
+							last = position
 						}
-						last = position
 					}
 				}
+				delegate?.addPieceToTarget(self, target: position)
 			}
 		}
 	}

Sources/Engine/Pieces/King.swift

@@ -1,6 +1,19 @@
 final class King: Piece {
 	typealias Threats = (Piece?, Piece?)
-	var threats: Threats = (nil, nil)
+	internal private(set) var threats: Threats = (nil, nil)
+
+	func insertThreat(_ piece: Piece) {
+		if threats.0 == nil {
+			threats.0 = piece
+			return
+		}
+
+		if threats.1 == nil {
+			threats.1 = piece
+			return
+		}
+	}
+
 	override var unicodeRepresentation: String {
 		return color == .Black ? "♚" : "♔"
 	}

Sources/Engine/Pieces/Queen.swift

@@ -31,13 +31,16 @@ final class Queen: Piece, LinearMoves, DiagonalMoves {
 						if let king = piece as? King {
 							delegate?.notify(.kingInCheck(self, on: king))
 							legalPositions.removeLast()
+							last = position
+							return
 						} else {
 							delegate?.notify(
 								.piecePinned(from: self, on: piece))
+							last = position
 						}
-						last = position
 					}
 				}
+				delegate?.addPieceToTarget(self, target: position)
 			}
 		}
 	}

Sources/Engine/Pieces/Rook.swift

@@ -29,13 +29,16 @@ final class Rook: Piece, LinearMoves {
 						if let king = piece as? King {
 							delegate?.notify(.kingInCheck(self, on: king))
 							legalPositions.removeLast()
+							last = position
+							return
 						} else {
 							delegate?.notify(
 								.piecePinned(from: self, on: piece))
+							last = position
 						}
-						last = position
 					}
 				}
+				delegate?.addPieceToTarget(self, target: position)
 			}
 		}
 	}