diff --git a/dev_deps.ts b/dev_deps.ts
new file mode 100644
index 0000000..d68d3be
--- /dev/null
+++ b/dev_deps.ts
@@ -0,0 +1 @@
+export { assertEquals } from "https://deno.land/std@0.160.0/testing/asserts.ts";
diff --git a/initRank.ts b/initRank.ts
new file mode 100644
index 0000000..daf315a
--- /dev/null
+++ b/initRank.ts
@@ -0,0 +1,112 @@
+/**
+ * If rankState in profile.json is not defined, it will be initialized.
+ */
+import { flags } from "./deps.ts";
+import { getBulletToken, getGToken } from "./src/iksm.ts";
+import { checkToken, getBattleDetail, getBattleList } from "./src/splatnet3.ts";
+import { gameId, readline } from "./src/utils.ts";
+import { FileStateBackend } from "./src/state.ts";
+import { BattleListType } from "./src/types.ts";
+import { RANK_PARAMS } from "./src/RankTracker.ts";
+
+const parseArgs = (args: string[]) => {
+  const parsed = flags.parse(args, {
+    string: ["profilePath"],
+    alias: {
+      "help": "h",
+      "profilePath": ["p", "profile-path"],
+    },
+  });
+  return parsed;
+};
+
+const opts = parseArgs(Deno.args);
+if (opts.help) {
+  console.log(
+    `Usage: deno run -A ${Deno.mainModule} [options]
+  
+  Options:
+      --profile-path <path>, -p    Path to config file (default: ./profile.json)
+      --help                       Show this help message and exit`,
+  );
+  Deno.exit(0);
+}
+
+const stateBackend = new FileStateBackend(opts.profilePath ?? "./profile.json");
+let state = await stateBackend.read();
+
+if (state.rankState) {
+  console.log("rankState is already initialized.");
+  Deno.exit(0);
+}
+
+if (!await checkToken(state)) {
+  const sessionToken = state.loginState?.sessionToken;
+
+  if (!sessionToken) {
+    throw new Error("Session token is not set.");
+  }
+
+  const { webServiceToken, userCountry, userLang } = await getGToken({
+    fApi: state.fGen,
+    sessionToken,
+  });
+
+  const bulletToken = await getBulletToken({
+    webServiceToken,
+    userLang,
+    userCountry,
+    appUserAgent: state.appUserAgent,
+  });
+
+  state = {
+    ...state,
+    loginState: {
+      ...state.loginState,
+      gToken: webServiceToken,
+      bulletToken,
+    },
+    userLang: state.userLang ?? userLang,
+    userCountry: state.userCountry ?? userCountry,
+  };
+  await stateBackend.write(state);
+}
+
+const battleList = await getBattleList(state, BattleListType.Bankara);
+if (battleList.length === 0) {
+  console.log("No anarchy battle found. Did you play anarchy?");
+  Deno.exit(0);
+}
+const { vsHistoryDetail: detail } = await getBattleDetail(state, battleList[0]);
+
+console.log(
+  `Your latest battle is played at ${
+    new Date(detail.playedTime).toLocaleString()
+  }. Please enter your rank after this battle(format: RANK,POINT. S+0,300):`,
+);
+
+while (true) {
+  const userInput = await readline();
+  const [rank, point] = userInput.split(",");
+  const pointNumber = parseInt(point);
+
+  if (!RANK_PARAMS.find((i) => i.rank === rank)) {
+    console.log("Invalid rank. Please enter again:");
+  } else if (isNaN(pointNumber)) {
+    console.log("Invalid point. Please enter again:");
+  } else {
+    state = {
+      ...state,
+      rankState: {
+        gameId: await gameId(detail.id),
+        rank,
+        rankPoint: pointNumber,
+      },
+    };
+
+    break;
+  }
+}
+
+await stateBackend.write(state);
+console.log("rankState is initialized.");
diff --git a/src/RankTracker.test.ts b/src/RankTracker.test.ts
new file mode 100644
index 0000000..4d99fa0
--- /dev/null
+++ b/src/RankTracker.test.ts
@@ -0,0 +1,7 @@
+import { RankTracker } from "./RankTracker.ts";
+import { assertEquals } from "../dev_deps.ts";
+
+Deno.test("RankTracker", () => {
+  const tracker = new RankTracker();
+  assertEquals(tracker, new RankTracker());
+});
diff --git a/src/RankTracker.ts b/src/RankTracker.ts
new file mode 100644
index 0000000..e2b14c0
--- /dev/null
+++ b/src/RankTracker.ts
@@ -0,0 +1,113 @@
+import { RankState } from "./state.ts";
+import { GameFetcher } from "./GameFetcher.ts";
+
+type RankParam = {
+  rank: string;
+  pointRange: [number, number];
+  entrance: number;
+  openWin: number;
+  openLose: number;
+  rankUp?: boolean;
+};
+
+const splusParams = () => {
+  const out: RankParam[] = [];
+
+  for (let i = 0; i < 50; i++) {
+    const level = i % 10;
+    const item: RankParam = {
+      rank: `S+${i}`,
+      pointRange: [300 + level * 350, 300 + (level + 1) * 350],
+      entrance: 160,
+      openWin: 8,
+      openLose: 5,
+    };
+    if (level === 9) {
+      item.rankUp = true;
+    }
+    out.push(item);
+  }
+
+  out.push({
+    rank: "S+50",
+    pointRange: [0, 9999],
+    entrance: 160,
+    openWin: 8,
+    openLose: 5,
+  });
+
+  return out;
+};
+
+export const RANK_PARAMS: RankParam[] = [{
+  rank: "C-",
+  pointRange: [0, 200],
+  entrance: 0,
+  openWin: 8,
+  openLose: 1,
+}, {
+  rank: "C",
+  pointRange: [200, 400],
+  entrance: 20,
+  openWin: 8,
+  openLose: 1,
+}, {
+  rank: "C+",
+  pointRange: [400, 600],
+  entrance: 40,
+  openWin: 8,
+  openLose: 1,
+  rankUp: true,
+}, {
+  rank: "B-",
+  pointRange: [100, 350],
+  entrance: 55,
+  openWin: 8,
+  openLose: 2,
+}, {
+  rank: "B",
+  pointRange: [350, 600],
+  entrance: 70,
+  openWin: 8,
+  openLose: 2,
+}, {
+  rank: "B+",
+  pointRange: [600, 850],
+  entrance: 85,
+  openWin: 8,
+  openLose: 2,
+  rankUp: true,
+}, {
+  rank: "A-",
+  pointRange: [200, 500],
+  entrance: 100,
+  openWin: 8,
+  openLose: 3,
+}, {
+  rank: "A",
+  pointRange: [500, 800],
+  entrance: 110,
+  openWin: 8,
+  openLose: 3,
+}, {
+  rank: "A+",
+  pointRange: [800, 1100],
+  entrance: 120,
+  openWin: 8,
+  openLose: 3,
+  rankUp: true,
+}, {
+  rank: "S",
+  pointRange: [300, 1000],
+  entrance: 150,
+  openWin: 8,
+  openLose: 4,
+  rankUp: true,
+}, ...splusParams()];
+
+/**
+ * if state is empty, it will not track rank.
+ */
+export class RankTracker {
+  constructor(private state?: RankState) {}
+}
diff --git a/src/state.ts b/src/state.ts
index fd611de..b03794a 100644
--- a/src/state.ts
+++ b/src/state.ts
@@ -3,6 +3,15 @@ export type LoginState = {
   gToken?: string;
   bulletToken?: string;
 };
+export type RankState = {
+  // generated by gameId(battle.id)
+  // If the gameId does not exist, the tracker will assume that the user has
+  // not played a bankara match. And it will start tracking from the first match
+  gameId?: string;
+  // C-, B, A+, S, S+0, S+12
+  rank: string;
+  rankPoint: number;
+};
 export type State = {
   loginState?: LoginState;
   fGen: string;
@@ -10,6 +19,8 @@ export type State = {
   userLang?: string;
   userCountry?: string;
 
+  rankState?: RankState;
+
   cacheDir: string;
 
   // Exporter config
diff --git a/src/utils.ts b/src/utils.ts
index cb4bf72..de5619d 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -19,9 +19,11 @@ export function urlBase64Decode(data: string) {
   );
 }
 
-export async function readline() {
+export async function readline(
+  { skipEmpty = true }: { skipEmpty?: boolean } = {},
+) {
   for await (const line of stdinLines) {
-    if (line !== "") {
+    if (!skipEmpty || line !== "") {
       return line;
     }
   }