diff --git a/board.h b/board.h
index 9a917e8..c03a5f7 100644
--- a/board.h
+++ b/board.h
@@ -84,12 +84,13 @@ class Board{
 	};
 
 private:
-	short size; //the length of one side of the hexagon
-	short size_d; //diameter of the board = size*2-1
+	char size; //the length of one side of the hexagon
+	char size_d; //diameter of the board = size*2-1
 
 	short nummoves;
 	char toPlay;
 	char outcome; //-1 = unknown, 0 = tie, 1,2 = player win
+	bool allowswap;
 
 	vector<Cell> cells;
 
@@ -104,6 +105,7 @@ class Board{
 		nummoves = 0;
 		toPlay = 1;
 		outcome = -1;
+		allowswap = true;
 
 		cells.resize(vecsize());
 
@@ -143,8 +145,8 @@ class Board{
 	bool onboard(int x, int y)  const { return (  x >= 0 &&   y >= 0 &&   x < size_d &&   y < size_d && onboard_fast(x, y) ); }
 	bool onboard(const Move & m)const { return (m.x >= 0 && m.y >= 0 && m.x < size_d && m.y < size_d && onboard_fast(m) ); }
 
-	bool canswap() const { return (nummoves == 1 && toPlay == 2); }
-//	bool canswap() const { return false; }
+	void setswap(bool s) { allowswap = s; }
+	bool canswap() const { return (nummoves == 1 && toPlay == 2 && allowswap); }
 
 	//assumes x, y are in bounds (meaning no swap) and the game isn't already finished
 	bool valid_move_fast(int x, int y)   const { return !get(x,y); }
diff --git a/solver.h b/solver.h
index 0d13f14..22b18ad 100644
--- a/solver.h
+++ b/solver.h
@@ -99,11 +99,11 @@ class Solver {
 	}
 	void timedout(){ timeout = true; }
 
-	void solve_ab     (const Board & board, double time, int mdepth = 1000);
-	void solve_scout  (const Board & board, double time, int mdepth = 1000);
-	void solve_pns    (const Board & board, double time, uint64_t memlimit);
-	void solve_pnsab  (const Board & board, double time, uint64_t memlimit);
-	void solve_dfpnsab(const Board & board, double time, uint64_t memlimit);
+	void solve_ab     (Board board, double time, int mdepth = 1000);
+	void solve_scout  (Board board, double time, int mdepth = 1000);
+	void solve_pns    (Board board, double time, uint64_t memlimit);
+	void solve_pnsab  (Board board, double time, uint64_t memlimit);
+	void solve_dfpnsab(Board board, double time, uint64_t memlimit);
 
 //protected:
 
diff --git a/solverab.cpp b/solverab.cpp
index c765f55..92a14d1 100644
--- a/solverab.cpp
+++ b/solverab.cpp
@@ -1,12 +1,13 @@
 
 #include "solver.h"
 
-void Solver::solve_ab(const Board & board, double time, int mdepth){
+void Solver::solve_ab(Board board, double time, int mdepth){
 	reset();
 	if(board.won() >= 0){
 		outcome = board.won();
 		return;
 	}
+	board.setswap(false);
 
 	Timer timer = Timer(time, bind(&Solver::timedout, this));
 	int starttime = time_msec();
diff --git a/solverdfpnsab.cpp b/solverdfpnsab.cpp
index 8807d52..341b52a 100644
--- a/solverdfpnsab.cpp
+++ b/solverdfpnsab.cpp
@@ -1,13 +1,14 @@
 
 #include "solver.h"
 
-void Solver::solve_dfpnsab(const Board & board, double time, uint64_t memlimit){
+void Solver::solve_dfpnsab(Board board, double time, uint64_t memlimit){
 	reset();
 
 	if(board.won() >= 0){
 		outcome = board.won();
 		return;
 	}
+	board.setswap(false);
 
 	Timer timer = Timer(time, bind(&Solver::timedout, this));
 	int starttime = time_msec();
diff --git a/solverpns.cpp b/solverpns.cpp
index f00ae8f..d5dc0aa 100644
--- a/solverpns.cpp
+++ b/solverpns.cpp
@@ -8,13 +8,14 @@
  * L W L  L   from the perspective of toplay
  * U W LT U
  */
-void Solver::solve_pns(const Board & board, double time, uint64_t memlimit){
+void Solver::solve_pns(Board board, double time, uint64_t memlimit){
 	reset();
 
 	if(board.won() >= 0){
 		outcome = board.won();
 		return;
 	}
+	board.setswap(false);
 
 	Timer timer = Timer(time, bind(&Solver::timedout, this));
 	int starttime = time_msec();
diff --git a/solverpnsab.cpp b/solverpnsab.cpp
index d08ff43..2aeba85 100644
--- a/solverpnsab.cpp
+++ b/solverpnsab.cpp
@@ -1,13 +1,14 @@
 
 #include "solver.h"
 
-void Solver::solve_pnsab(const Board & board, double time, uint64_t memlimit){
+void Solver::solve_pnsab(Board board, double time, uint64_t memlimit){
 	reset();
 
 	if(board.won() >= 0){
 		outcome = board.won();
 		return;
 	}
+	board.setswap(false);
 
 	Timer timer = Timer(time, bind(&Solver::timedout, this));
 	int starttime = time_msec();
diff --git a/solverscout.cpp b/solverscout.cpp
index ce46faf..7abf062 100644
--- a/solverscout.cpp
+++ b/solverscout.cpp
@@ -1,12 +1,13 @@
 
 #include "solver.h"
 
-void Solver::solve_scout(const Board & board, double time, int mdepth){
+void Solver::solve_scout(Board board, double time, int mdepth){
 	reset();
 	if(board.won() >= 0){
 		outcome = board.won();
 		return;
 	}
+	board.setswap(false);
 
 	Timer timer = Timer(time, bind(&Solver::timedout, this));
 	int starttime = time_msec();