diff --git a/pkg/game/game.go b/pkg/game/game.go
index 7bc4b22..c14ba3e 100644
--- a/pkg/game/game.go
+++ b/pkg/game/game.go
@@ -7,6 +7,7 @@ import (
 	"github.com/google/uuid"
 	"github.com/iliadenisov/galaxy/pkg/generator"
 	"github.com/iliadenisov/galaxy/pkg/model/game"
+	"github.com/iliadenisov/galaxy/pkg/number"
 )
 
 type Repo interface {
@@ -198,7 +199,7 @@ func (sg ShipGroup) BombingPower() float64 {
 		sg.Weapons *
 		float64(sg.Type.Armament) *
 		float64(sg.Number)
-	return toFixed3(result)
+	return number.Fixed3(result)
 }
 
 // TODO: test this
@@ -211,17 +212,3 @@ func (fl Fleet) Speed() float64 {
 	}
 	return result
 }
-
-func round(num float64) int {
-	return int(num + math.Copysign(0.5, num))
-}
-
-// TODO: move to more common place
-func toFixed(num float64, precision int) float64 {
-	output := math.Pow(10, float64(precision))
-	return float64(round(num*output)) / output
-}
-
-func toFixed3(num float64) float64 {
-	return toFixed(num, 3)
-}
diff --git a/pkg/generator/generator.go b/pkg/generator/generator.go
index d2079c8..faf56c5 100644
--- a/pkg/generator/generator.go
+++ b/pkg/generator/generator.go
@@ -37,18 +37,18 @@ func Generate(cfg ...func(*MapSetting)) (Map, error) {
 
 	// 3. Place players' Home Worlds
 	for player := 0; player < int(ms.Players); player++ {
-		coord, err := m.NewCoordinate(float64(ms.HWMinDistance))
+		hwCoord, err := m.NewCoordinate(float64(ms.HWMinDistance))
 		if err != nil {
 			return Map{}, fmt.Errorf("%s: hw new_coordinate: %s", ms, err)
 		}
-		planet := NewPlanet(coord, float64(ms.HWSize), float64(ms.HWResources))
-		m.HomePlanets[player] = PlanetarySystem{HW: planet, DW: make([]Planet, ms.DWCount)}
+		hwPlanet := NewPlanet(hwCoord, float64(ms.HWSize), float64(ms.HWResources))
+		m.HomePlanets[player] = PlanetarySystem{HW: hwPlanet, DW: make([]Planet, ms.DWCount)}
 		for dw := 0; dw < int(ms.DWCount); dw++ {
 			p := rand.Float64()*(float64(ms.DWMaxDistance)-float64(ms.DWMinDistance)) + float64(ms.DWMinDistance)
 			phi := rand.Float64() * 360
 			x := p * math.Cos(phi)
 			y := p * math.Sin(phi)
-			dwPlanet := NewPlanet(Coordinate{x, y}, float64(ms.DWSize), float64(ms.DWResources))
+			dwPlanet := NewPlanet(Coordinate{hwCoord.X + x, hwCoord.Y + y}, float64(ms.DWSize), float64(ms.DWResources))
 			m.HomePlanets[player].DW[dw] = dwPlanet
 		}
 	}
diff --git a/pkg/generator/generator_test.go b/pkg/generator/generator_test.go
index d318300..df1ef8f 100644
--- a/pkg/generator/generator_test.go
+++ b/pkg/generator/generator_test.go
@@ -22,6 +22,13 @@ func TestGenerator(t *testing.T) {
 		assert.Equal(t, players, len(m.HomePlanets), "hw count")
 		for i := range m.HomePlanets {
 			assert.Equal(t, int(s.DWCount), len(m.HomePlanets[i].DW), "hw #%d: dw count", i)
+			for dw := range m.HomePlanets[i].DW {
+				d := m.ShortDistance(m.HomePlanets[i].HW.Position, m.HomePlanets[i].DW[dw].Position)
+				assert.LessOrEqualf(t, float64(s.DWMinDistance), d, "HW[%.04f,%04f] - DW[%.04f,%04f]",
+					m.HomePlanets[i].HW.Position.X, m.HomePlanets[i].HW.Position.Y, m.HomePlanets[i].DW[dw].Position.X, m.HomePlanets[i].DW[dw].Position.Y)
+				assert.GreaterOrEqualf(t, float64(s.DWMaxDistance), d, "HW[%.04f,%04f] - DW[%.04f,%04f]",
+					m.HomePlanets[i].HW.Position.X, m.HomePlanets[i].HW.Position.Y, m.HomePlanets[i].DW[dw].Position.X, m.HomePlanets[i].DW[dw].Position.Y)
+			}
 		}
 	}
 }
diff --git a/pkg/generator/map.go b/pkg/generator/map.go
index e128a32..16abd02 100644
--- a/pkg/generator/map.go
+++ b/pkg/generator/map.go
@@ -2,6 +2,7 @@ package generator
 
 import (
 	"fmt"
+	"math"
 	"math/rand"
 
 	"github.com/iliadenisov/galaxy/pkg/generator/plotter"
@@ -67,6 +68,18 @@ func (m Map) NewCoordinate(deadZoneRaduis float64) (Coordinate, error) {
 	}
 }
 
+func (m Map) ShortDistance(from, to Coordinate) float64 {
+	dx := math.Abs(to.X - from.X)
+	dy := math.Abs(to.Y - from.Y)
+	if dx > float64(m.Width/2) {
+		dx = float64(m.Width) - dx
+	}
+	if dy > float64(m.Height/2) {
+		dy = float64(m.Height) - dy
+	}
+	return math.Sqrt(math.Pow(dx, 2) + math.Pow(dy, 2))
+}
+
 func NewPlanet(c Coordinate, size, resources float64) Planet {
 	return Planet{
 		Position:  c,
diff --git a/pkg/generator/map_test.go b/pkg/generator/map_test.go
new file mode 100644
index 0000000..dd8c054
--- /dev/null
+++ b/pkg/generator/map_test.go
@@ -0,0 +1,27 @@
+package generator
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/iliadenisov/galaxy/pkg/number"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestShortDistance(t *testing.T) {
+	for i, tc := range []struct {
+		w, h              uint32
+		x1, y1, x2, y2, d float64
+	}{
+		{10, 10, 0, 0, 5, 5, 7.071},
+		{10, 10, 0, 0, 5.01, 5.01, 7.057},
+		{10, 10, 2, 2, 8, 2, 4.},
+		{10, 10, 8, 7, 1, 7, 3.},
+	} {
+		t.Run(fmt.Sprint(i), func(t *testing.T) {
+			m := Map{Width: tc.w, Height: tc.h}
+			d := m.ShortDistance(Coordinate{tc.x1, tc.y1}, Coordinate{tc.x2, tc.y2})
+			assert.Equal(t, tc.d, number.Fixed3(d))
+		})
+	}
+}
diff --git a/pkg/model/game/ship.go b/pkg/model/game/ship.go
index b7d7b0c..d21968d 100644
--- a/pkg/model/game/ship.go
+++ b/pkg/model/game/ship.go
@@ -1,6 +1,10 @@
 package game
 
-import "math"
+import (
+	"math"
+
+	"github.com/iliadenisov/galaxy/pkg/number"
+)
 
 type Ship struct {
 	TypeName string
@@ -103,7 +107,7 @@ func (sg ShipGroup) BombingPower() float64 {
 		sg.Weapons *
 		float64(sg.Type.Armament) *
 		float64(sg.Number)
-	return toFixed3(result)
+	return number.Fixed3(result)
 }
 
 // TODO: test this
@@ -116,17 +120,3 @@ func (fl Fleet) Speed() float64 {
 	}
 	return result
 }
-
-func toFixed3(num float64) float64 {
-	return toFixed(num, 3)
-}
-
-// TODO: move to more common place
-func toFixed(num float64, precision int) float64 {
-	output := math.Pow(10, float64(precision))
-	return float64(round(num*output)) / output
-}
-
-func round(num float64) int {
-	return int(num + math.Copysign(0.5, num))
-}
diff --git a/pkg/number/number.go b/pkg/number/number.go
new file mode 100644
index 0000000..51d5308
--- /dev/null
+++ b/pkg/number/number.go
@@ -0,0 +1,16 @@
+package number
+
+import "math"
+
+func Fixed3(num float64) float64 {
+	return fixed(num, 3)
+}
+
+func fixed(num float64, precision int) float64 {
+	output := math.Pow(10, float64(precision))
+	return float64(round(num*output)) / output
+}
+
+func round(num float64) int {
+	return int(num + math.Copysign(0.5, num))
+}