diff --git a/README.md b/README.md
index e69de29b..da07bf41 100644
--- a/README.md
+++ b/README.md
@@ -0,0 +1,41 @@
+
+
+## 기능목록
+
+여기서 게임은 숫자야구게임 1판을 의미한다 (새로운 정답을 만들고 유저가 맞출 때까지 시도)
+
+- [x] 게임을 반복하는 기능 (유저에게 계속할지를 물어봄)
+- [x] 게임을 진행하는 기능
+- [x] 숫자야구게임의 볼조합을 생성하는 기능
+- [x] 두 볼조합을 통해 결과를 생성하는 기능
+- [x] 생성된 결과를 유저가 보기 쉬운 메세지로 만들기
+
+## 어떻게 구현할까?? 
+
+1. junit 관련 살펴보기 (간단한 예제 + 탐험)
+2. mockito 를 이용한 간단한 테스트
+3. README.md 작성
+4. 각 기능 구현 (가능하면 테스트랑 같이)
+5. 컨벤션 확인 (리뷰)
+
+- 일단 자바 문법에 익숙해졌으면 (최소한 자주 쓸 부분은)
+- 테스트코드를 작성하는 이유중 하나도 코드를 막 고쳐보기 위함 (특히 여러가지 자료구조등을 사용해보고 연습해보고 싶어서) 
+
+
+
+
+### test
+
+// 테스트 객체 개념
+https://medium.com/@SlackBeck/mock-object%EB%9E%80-%EB%AC%B4%EC%97%87%EC%9D%B8%EA%B0%80-85159754b2ac 
+
+// Intellij Idea junit
+https://examples.javacodegeeks.com/desktop-java/ide/intellij-idea-create-test-tutorial/
+https://www.jetbrains.com/help/idea/tdd-with-intellij-idea.html
+
+
+### 자바 익숙해지기...
+https://1nyoung.tistory.com/14
+https://jdm.kr/blog/181
+https://github.com/winterbe/java8-tutorial
+https://www.acmicpc.net/blog/view/3
\ No newline at end of file
diff --git a/src/main/java/BallCombiGenerator.java b/src/main/java/BallCombiGenerator.java
new file mode 100644
index 00000000..acce5bea
--- /dev/null
+++ b/src/main/java/BallCombiGenerator.java
@@ -0,0 +1,59 @@
+import java.util.Arrays;
+import java.util.Random;
+import java.util.stream.IntStream;
+
+import static java.lang.Integer.max;
+
+public class BallCombiGenerator {
+
+    public int[] genBallCombi() {
+        Random rand = new Random();
+
+        int [] ballPnts = IntStream.range(1, 10).toArray();
+
+        // shuffle ballPnts
+        for (int from = 0; from < ballPnts.length; from++) {
+            int to = rand.nextInt(ballPnts.length);
+
+            int tmp = ballPnts[from];
+            ballPnts[from] = ballPnts[to];
+            ballPnts[to] = tmp;
+        }
+
+        return Arrays.copyOfRange(ballPnts, 0, 3);
+    }
+
+    public boolean isValid(int[] ballCombi) {
+        if (ballCombi.length != 3) return false;
+
+        for (int i = 0; i < ballCombi.length; i++) {
+            int pnt = ballCombi[i];
+            if (pnt <= 0 || 10 <= pnt) return false;
+        }
+
+        // check duplicated number
+        int [] pntCnt = new int[10];
+        Arrays.stream(ballCombi).forEach((pnt) -> pntCnt[pnt]++);
+
+        int maxPntCnt =  Arrays.stream(ballCombi)
+                .map(pnt -> pntCnt[pnt])
+                .reduce((a, b) -> max(a, b))
+                .getAsInt();
+
+        return maxPntCnt <= 1;
+    }
+
+    public int[] toBallCombi(String ballCombiStr) {
+        if (ballCombiStr.length() != 3) return new int[0];
+
+        int [] ballCombi = new int[3];
+        for (int i = 0; i < ballCombiStr.length(); i++) {
+            char c = ballCombiStr.charAt(i);
+            if (c <= '0' || '9' < c) return new int[0];
+
+            ballCombi[i] = c - '0';
+        }
+
+        return ballCombi;
+    }
+}
diff --git a/src/main/java/Game.java b/src/main/java/Game.java
new file mode 100644
index 00000000..f3d42a1e
--- /dev/null
+++ b/src/main/java/Game.java
@@ -0,0 +1,62 @@
+import java.util.Scanner;
+
+public class Game {
+
+    final private int STRIKE = 0;
+    final private int BALL = 1;
+
+    private Scanner sc;
+    private BallCombiGenerator generator;
+    private Referee referee;
+
+    public Game() {
+        sc = new Scanner(System.in);
+        generator = new BallCombiGenerator();
+        referee = new Referee();
+    }
+
+    public void play() {
+
+        int [] ansBallCombi = generator.genBallCombi();
+
+        for (int trial = 1; ; trial++) {
+            int [] userBallCombi;
+
+            System.out.printf("숫자를 입력해주세요: ");
+            String userBallCombiStr = sc.next(); //
+            userBallCombi = generator.toBallCombi(userBallCombiStr);
+            while (!generator.isValid(userBallCombi)) {
+                System.out.printf("잘못된 입력입니다. 숫자를 입력해주세요: ");
+                userBallCombiStr = sc.next(); //
+                userBallCombi = generator.toBallCombi(userBallCombiStr);
+            }
+
+            int [] judgement = referee.judge(ansBallCombi, userBallCombi);
+
+            if (judgement[STRIKE] == 3) {
+                System.out.printf("3개의 숫자를 모두 맞히셨습니다! 게임 종료 (%d 시도)\n", trial);
+                break;
+            }
+
+            printJudgement(judgement);
+        }
+    }
+
+    private void printJudgement(int [] judgement) {
+        if (judgement[STRIKE] == 0 && judgement[BALL] == 0) {
+            System.out.println("낫싱");
+        }
+
+        String str = "";
+
+        if (0 < judgement[STRIKE]) {
+            str += String.format("%d 스트라이크 ", judgement[STRIKE]);
+        }
+
+        if (0 < judgement[BALL]) {
+            str += String.format("%d 볼", judgement[BALL]);
+        }
+
+        System.out.println(str);
+    }
+}
diff --git a/src/main/java/GameExecutor.java b/src/main/java/GameExecutor.java
new file mode 100644
index 00000000..e71fa14c
--- /dev/null
+++ b/src/main/java/GameExecutor.java
@@ -0,0 +1,18 @@
+import java.util.Scanner;
+
+public class GameExecutor {
+    public static void main(String[] args) {
+
+        Scanner sc = new Scanner(System.in);
+        // 지금은 아무 상태도 가지고 있지 않기에 동일한 game을 사용
+        Game game = new Game();
+
+        while (true) {
+            game.play();
+
+            System.out.println("게임을 새로 시작하려면 1, 종료하려면 2를 입력하세요. ");
+
+            if (2 == sc.nextInt()) break;
+        }
+    }
+}
diff --git a/src/main/java/Referee.java b/src/main/java/Referee.java
new file mode 100644
index 00000000..d16760b1
--- /dev/null
+++ b/src/main/java/Referee.java
@@ -0,0 +1,28 @@
+import java.util.Arrays;
+import java.util.stream.IntStream;
+
+public class Referee {
+
+    public int[] judge(int[] ansBallCombi, int[] inpBallCombi) {
+        int[] cnt = new int[10];
+
+        for (int ansPnt : ansBallCombi) {
+            cnt[ansPnt]++;
+        }
+
+        int strikeCnt = IntStream.range(0, inpBallCombi.length)
+                .map(i -> (ansBallCombi[i] == inpBallCombi[i]) ? 1 : 0)
+                .reduce((a, b) -> a + b)
+                .getAsInt();
+
+        int ballCnt = Arrays.stream(inpBallCombi)
+                .map(pnt -> cnt[pnt])
+                .reduce((a, b) -> a + b)
+                .getAsInt()
+                - strikeCnt;
+
+        int[] judgement = {strikeCnt, ballCnt};
+
+        return judgement;
+    }
+}
diff --git a/src/test/java/BallCombiGeneratorTest.java b/src/test/java/BallCombiGeneratorTest.java
new file mode 100644
index 00000000..600340d4
--- /dev/null
+++ b/src/test/java/BallCombiGeneratorTest.java
@@ -0,0 +1,124 @@
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+
+public class BallCombiGeneratorTest {
+
+    private BallCombiGenerator generator;
+
+    @Before
+    public void setUp() throws Exception {
+        generator = new BallCombiGenerator();
+    }
+
+    @Test
+    public void genBallCombi_generatedBallCombiAllValid() {
+        int n = 100;
+
+        for (int i = 0; i < n; i++) {
+            int [] ballCombi = generator.genBallCombi();
+//            System.out.println(Arrays.toString(ballCombi));
+//            System.out.flush();
+
+            boolean got = generator.isValid(ballCombi);
+
+            Assert.assertTrue(String.format("[%d] got: %b\n", i, got), got);
+        }
+    }
+
+    @Test
+    public void isValid_possibleValidBallCombis() {
+        // 입력
+        int [][] possibleBallCombis = genPossibleBallCombis();
+
+        for (int [] ballCombi: possibleBallCombis) {
+//            System.out.println(Arrays.toString(ballCombi));
+//            System.out.flush();
+            boolean got = generator.isValid(ballCombi);
+            Assert.assertTrue(String.format("ballCombi: %s", Arrays.toString(ballCombi)), got);
+        }
+    }
+
+
+    @Test
+    public void isValid_invalidBallCombis() {
+        // 입력
+        int [][] ballCombis = {
+                {1, 1, 1, 1},
+                {0, 1, 2},
+                {1, 2, 2},
+                {9, 9, 9},
+        };
+
+        for(int i = 0; i < ballCombis.length; i++) {
+            int [] ballCombi = ballCombis[i];
+
+            boolean got = generator.isValid(ballCombi);
+
+            Assert.assertFalse(String.format("[%d] ", i), got);
+        }
+    }
+
+    @Test
+    public void toBallCombi_usualInputStr() {
+        //
+        String [] strs = {
+                "hello",
+                "012344",
+                "adkfj",
+                "023",
+                "987",
+                "345",
+        };
+
+        int [][] wants = {
+                {},
+                {},
+                {},
+                {},
+                {9, 8, 7},
+                {3, 4, 5},
+        };
+
+        for (int i = 0; i < strs.length; i++) {
+            String str = strs[i];
+            int [] want = wants[i];
+
+            int [] got = generator.toBallCombi(str);
+
+            Assert.assertArrayEquals(
+                    String.format("[%d] want: %s, got: %s", i, Arrays.toString(want), Arrays.toString(got)),
+                    want,
+                    got
+            );
+        }
+    }
+
+    private int[][] genPossibleBallCombis() {
+        int used[] = new int [10];
+
+        ArrayList<int[]> combis = new ArrayList<>();
+
+        for (int p1 = 1; p1 <= 9; p1++) {
+            used[p1]++;
+            for (int p2 = 1; p2 <= 9; p2++) {
+                if (used[p2] != 0) continue;
+                used[p2]++;
+                for(int p3 = 1; p3 <= 9; p3++) {
+                    if (used[p3] != 0) continue;
+
+                    // 생성해서 바로 넣는 방법이 없으려나??..
+                    int [] ballCombi = {p1, p2, p3};
+                    combis.add(ballCombi);
+                }
+                used[p2]--;
+            }
+            used[p1]--;
+        }
+
+        return combis.toArray(new int[combis.size()][]);
+    }
+}
diff --git a/src/test/java/RefereeTest.java b/src/test/java/RefereeTest.java
new file mode 100644
index 00000000..d78c6813
--- /dev/null
+++ b/src/test/java/RefereeTest.java
@@ -0,0 +1,53 @@
+import org.junit.Assert;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.util.Arrays;
+
+public class RefereeTest {
+
+    private Referee referee;
+
+    @Before
+    public void setUp() throws Exception {
+        referee = new Referee();
+    }
+
+    @Test
+    public void judge_usualCases() {
+        int [] ansBallCombi = {1, 2, 3};
+        int [][] inpBallCombis = {
+                {1, 2, 3}, // 3s, 0b
+                {1, 3, 2}, // 1s, 2b
+                {2, 1, 3}, // 1s, 2b
+                {2, 3, 1}, // 0s, 3b
+                {9, 2, 5}, // 1s, 0b
+                {3, 4, 5}, // 0s, 1b
+                {4, 5, 6}, // 0s, 0b
+                {6, 2, 5}, // 1s, 0b
+        };
+        int [][] wants = {
+                {3, 0},
+                {1, 2},
+                {1, 2},
+                {0, 3},
+                {1, 0},
+                {0, 1},
+                {0, 0},
+                {1, 0},
+        };
+
+        for (int i = 0; i < wants.length; i++) {
+            int [] inpBallCombi = inpBallCombis[i];
+            int [] want = wants[i];
+
+            int [] got = referee.judge(ansBallCombi, inpBallCombi);
+
+            Assert.assertArrayEquals(String.format("[%d] want: %s, got: %s", i, Arrays.toString(want), Arrays.toString(got)),
+                    want,
+                    got
+            );
+        }
+    }
+}
+