diff --git a/challengeA/tokiwa_takumi/.gitignore b/challengeA/tokiwa_takumi/.gitignore
new file mode 100644
index 000000000..f05cf8c8d
--- /dev/null
+++ b/challengeA/tokiwa_takumi/.gitignore
@@ -0,0 +1 @@
+/spec/examples.txt
diff --git a/challengeA/tokiwa_takumi/.rspec b/challengeA/tokiwa_takumi/.rspec
new file mode 100644
index 000000000..c99d2e739
--- /dev/null
+++ b/challengeA/tokiwa_takumi/.rspec
@@ -0,0 +1 @@
+--require spec_helper
diff --git a/challengeA/tokiwa_takumi/Gemfile b/challengeA/tokiwa_takumi/Gemfile
new file mode 100644
index 000000000..c8b0363b5
--- /dev/null
+++ b/challengeA/tokiwa_takumi/Gemfile
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+ source "https://rubygems.org"
+
+ git_source(:github) {|repo_name| "https://github.com/#{repo_name}" }
+
+ gem "rspec"
+ 
\ No newline at end of file
diff --git a/challengeA/tokiwa_takumi/Gemfile.lock b/challengeA/tokiwa_takumi/Gemfile.lock
new file mode 100644
index 000000000..be655ec0c
--- /dev/null
+++ b/challengeA/tokiwa_takumi/Gemfile.lock
@@ -0,0 +1,26 @@
+GEM
+  remote: https://rubygems.org/
+  specs:
+    diff-lcs (1.4.4)
+    rspec (3.10.0)
+      rspec-core (~> 3.10.0)
+      rspec-expectations (~> 3.10.0)
+      rspec-mocks (~> 3.10.0)
+    rspec-core (3.10.1)
+      rspec-support (~> 3.10.0)
+    rspec-expectations (3.10.1)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.10.0)
+    rspec-mocks (3.10.2)
+      diff-lcs (>= 1.2.0, < 2.0)
+      rspec-support (~> 3.10.0)
+    rspec-support (3.10.2)
+
+PLATFORMS
+  ruby
+
+DEPENDENCIES
+  rspec
+
+BUNDLED WITH
+   2.1.2
diff --git a/challengeA/tokiwa_takumi/csv/jxtg/basic_charge.csv b/challengeA/tokiwa_takumi/csv/jxtg/basic_charge.csv
new file mode 100644
index 000000000..17285d199
--- /dev/null
+++ b/challengeA/tokiwa_takumi/csv/jxtg/basic_charge.csv
@@ -0,0 +1,5 @@
+ampere,basic_charge
+30,858.00
+40,1144.00
+50,1430.00
+60,1716.00
\ No newline at end of file
diff --git a/challengeA/tokiwa_takumi/csv/jxtg/info.csv b/challengeA/tokiwa_takumi/csv/jxtg/info.csv
new file mode 100644
index 000000000..14f58d9ae
--- /dev/null
+++ b/challengeA/tokiwa_takumi/csv/jxtg/info.csv
@@ -0,0 +1,2 @@
+provider_name,plan_name
+JXTGでんき,従量電灯Bたっぷりプラン
\ No newline at end of file
diff --git a/challengeA/tokiwa_takumi/csv/jxtg/usage_charge.csv b/challengeA/tokiwa_takumi/csv/jxtg/usage_charge.csv
new file mode 100644
index 000000000..5a87cb863
--- /dev/null
+++ b/challengeA/tokiwa_takumi/csv/jxtg/usage_charge.csv
@@ -0,0 +1,5 @@
+greater_than,less_than,unit_charge
+0,120,19.88
+120,300,26.48
+300,600,25.08
+600,,26.15
\ No newline at end of file
diff --git a/challengeA/tokiwa_takumi/csv/looop/basic_charge.csv b/challengeA/tokiwa_takumi/csv/looop/basic_charge.csv
new file mode 100644
index 000000000..5a58ea5a9
--- /dev/null
+++ b/challengeA/tokiwa_takumi/csv/looop/basic_charge.csv
@@ -0,0 +1,7 @@
+ampere,basic_charge
+10,0.00
+20,0.00
+30,0.00
+40,0.00
+50,0.00
+60,0.00
\ No newline at end of file
diff --git a/challengeA/tokiwa_takumi/csv/looop/info.csv b/challengeA/tokiwa_takumi/csv/looop/info.csv
new file mode 100644
index 000000000..e5c2b1a54
--- /dev/null
+++ b/challengeA/tokiwa_takumi/csv/looop/info.csv
@@ -0,0 +1,2 @@
+provider_name,plan_name
+Looopでんき,おうちプラン
\ No newline at end of file
diff --git a/challengeA/tokiwa_takumi/csv/looop/usage_charge.csv b/challengeA/tokiwa_takumi/csv/looop/usage_charge.csv
new file mode 100644
index 000000000..77eb6f09e
--- /dev/null
+++ b/challengeA/tokiwa_takumi/csv/looop/usage_charge.csv
@@ -0,0 +1,2 @@
+greater_than,less_than,unit_charge
+0,,26.40
\ No newline at end of file
diff --git a/challengeA/tokiwa_takumi/csv/tepco/basic_charge.csv b/challengeA/tokiwa_takumi/csv/tepco/basic_charge.csv
new file mode 100644
index 000000000..93eb363fa
--- /dev/null
+++ b/challengeA/tokiwa_takumi/csv/tepco/basic_charge.csv
@@ -0,0 +1,8 @@
+ampere,basic_charge
+10,286.00
+15,419.00
+20,572.00
+30,858.00
+40,1144.00
+50,1430.00
+60,1716.00
\ No newline at end of file
diff --git a/challengeA/tokiwa_takumi/csv/tepco/info.csv b/challengeA/tokiwa_takumi/csv/tepco/info.csv
new file mode 100644
index 000000000..dc1a3549f
--- /dev/null
+++ b/challengeA/tokiwa_takumi/csv/tepco/info.csv
@@ -0,0 +1,2 @@
+provider_name,plan_name
+東京電力エナジーパートナー,従量電灯B
\ No newline at end of file
diff --git a/challengeA/tokiwa_takumi/csv/tepco/usage_charge.csv b/challengeA/tokiwa_takumi/csv/tepco/usage_charge.csv
new file mode 100644
index 000000000..40f568915
--- /dev/null
+++ b/challengeA/tokiwa_takumi/csv/tepco/usage_charge.csv
@@ -0,0 +1,4 @@
+greater_than,less_than,unit_charge
+0,120,19.88
+120,300,26.48
+300,,30.57
\ No newline at end of file
diff --git a/challengeA/tokiwa_takumi/csv/tokyo_gas/basic_charge.csv b/challengeA/tokiwa_takumi/csv/tokyo_gas/basic_charge.csv
new file mode 100644
index 000000000..17285d199
--- /dev/null
+++ b/challengeA/tokiwa_takumi/csv/tokyo_gas/basic_charge.csv
@@ -0,0 +1,5 @@
+ampere,basic_charge
+30,858.00
+40,1144.00
+50,1430.00
+60,1716.00
\ No newline at end of file
diff --git a/challengeA/tokiwa_takumi/csv/tokyo_gas/info.csv b/challengeA/tokiwa_takumi/csv/tokyo_gas/info.csv
new file mode 100644
index 000000000..9457d9b77
--- /dev/null
+++ b/challengeA/tokiwa_takumi/csv/tokyo_gas/info.csv
@@ -0,0 +1,2 @@
+provider_name,plan_name
+東京ガス,ずっともでんき１
\ No newline at end of file
diff --git a/challengeA/tokiwa_takumi/csv/tokyo_gas/usage_charge.csv b/challengeA/tokiwa_takumi/csv/tokyo_gas/usage_charge.csv
new file mode 100644
index 000000000..98c5cd088
--- /dev/null
+++ b/challengeA/tokiwa_takumi/csv/tokyo_gas/usage_charge.csv
@@ -0,0 +1,4 @@
+greater_than,less_than,unit_charge
+0,140,23.67
+140,350,23.88
+350,,26.41
\ No newline at end of file
diff --git a/challengeA/tokiwa_takumi/lib/csv_plan.rb b/challengeA/tokiwa_takumi/lib/csv_plan.rb
new file mode 100644
index 000000000..a3a782847
--- /dev/null
+++ b/challengeA/tokiwa_takumi/lib/csv_plan.rb
@@ -0,0 +1,38 @@
+require 'csv'
+require_relative 'plan'
+
+class CSVPlan
+  attr_reader :provider_name, :plan_name, :basic_charge_list, :usage_charge_list
+
+  def initialize(provider_name, plan_name, basic_charge_list, usage_charge_list)
+    @provider_name = provider_name
+    @plan_name = plan_name
+    @basic_charge_list = basic_charge_list
+    @usage_charge_list = usage_charge_list
+  end
+
+  def convert_to_plan
+    Plan.new(
+      provider_name,
+      plan_name,
+      basic_charge_list,
+      usage_charge_list
+    )
+  end
+
+  class << self
+    def create_list_from_csv
+      plans = []
+      plans_dir = Dir.glob('../csv/*', base: __dir__)
+      plans_dir.each do |plan|
+        info = CSV.table(File.expand_path("./#{plan}/info.csv", __dir__))
+        plans << CSVPlan.new(info[:provider_name][0],
+                             info[:plan_name][0],
+                             CSV.read(File.expand_path("./#{plan}/basic_charge.csv", __dir__), headers: true).map(&:to_hash),
+                             CSV.read(File.expand_path("./#{plan}/usage_charge.csv", __dir__), headers: true).map(&:to_hash)
+        )
+      end
+      plans
+    end
+  end
+end
diff --git a/challengeA/tokiwa_takumi/lib/plan.rb b/challengeA/tokiwa_takumi/lib/plan.rb
new file mode 100644
index 000000000..b79537e85
--- /dev/null
+++ b/challengeA/tokiwa_takumi/lib/plan.rb
@@ -0,0 +1,32 @@
+class Plan
+  attr_reader :provider_name, :plan_name, :basic_charge_list, :usage_charge_list
+
+  def initialize(provider_name, plan_name, basic_charge_list, usage_charge_list)
+    @provider_name = provider_name
+    @plan_name = plan_name
+    @basic_charge_list = basic_charge_list
+    @usage_charge_list = usage_charge_list
+  end
+
+  def basic_charge(ampere)
+    basic_charge_plan = basic_charge_list.find{ |c| c["ampere"].to_i == ampere }
+    basic_charge_plan["basic_charge"].to_i unless basic_charge_plan.nil?
+  end
+
+  def usage_charge(monthly_amount_kwh)
+    charge = 0
+    usage_charge_list.each do |usage_charge|
+      gt = usage_charge["greater_than"].to_i
+      lt = usage_charge["less_than"].to_i
+      unit_charge = usage_charge["unit_charge"].to_f
+      if lt.zero? && gt < monthly_amount_kwh # 最大区分
+        charge += (monthly_amount_kwh - gt) * unit_charge
+      elsif lt <= monthly_amount_kwh && !lt.zero? # 超過する区分
+        charge += (lt - gt) * unit_charge
+      elsif gt < monthly_amount_kwh && monthly_amount_kwh < lt # 超過しない区分
+        charge += (monthly_amount_kwh - gt) * unit_charge
+      end
+    end
+    charge
+  end
+end
diff --git a/challengeA/tokiwa_takumi/lib/simulator.rb b/challengeA/tokiwa_takumi/lib/simulator.rb
new file mode 100644
index 000000000..dfe778406
--- /dev/null
+++ b/challengeA/tokiwa_takumi/lib/simulator.rb
@@ -0,0 +1,34 @@
+require_relative 'csv_plan'
+
+class Simulator
+
+  def initialize(ampere, monthly_amount_kwh)
+    @ampere = ampere
+    @monthly_amount_kwh = monthly_amount_kwh
+    suggest_plan
+  end
+
+  def simulate
+    @suggest_plans.flatten
+  end
+
+  private
+
+  def suggest_plan
+    @suggest_plans = []
+    plan_list = CSVPlan.create_list_from_csv.map(&:convert_to_plan)
+    @suggest_plans = plan_list.map{ |plan| simulate_charge(plan) }
+  end
+
+  def simulate_charge(plan)
+    basic_charge = plan.basic_charge(@ampere)
+    return if basic_charge.nil? ## 対応するアンペアなし
+
+    price = basic_charge + plan.usage_charge(@monthly_amount_kwh)
+    {
+      "provider_name": plan.provider_name,
+      "plan_name": plan.plan_name,
+      "price": price
+    }
+  end
+end
diff --git a/challengeA/tokiwa_takumi/spec/plan_spec.rb b/challengeA/tokiwa_takumi/spec/plan_spec.rb
new file mode 100644
index 000000000..c106ce630
--- /dev/null
+++ b/challengeA/tokiwa_takumi/spec/plan_spec.rb
@@ -0,0 +1,119 @@
+require "spec_helper"
+
+RSpec.describe Plan do
+  let!(:plan) { CSVPlan.create_list_from_csv.map(&:convert_to_plan) }
+
+  describe "東京ガスずっともでんき１" do
+    let!(:tokyo_gas) { plan.find{ |plan| plan.provider_name == "東京ガス" }}
+
+    describe "基本料金の算出が正しいこと" do
+      it "対応アンペアが存在する" do
+        expect(tokyo_gas.basic_charge(30)).to eq 858
+      end
+
+      it "対応アンペアが存在しない" do
+        expect(tokyo_gas.basic_charge(100)).to eq nil
+      end
+    end
+
+    describe "従量課金料金の算出が正しいこと" do
+      it "1つの区分で収まる使用量で算出する" do
+        expect(tokyo_gas.usage_charge(100)).to eq (23.67 * 100)
+      end
+
+      it "2つ以上の区分にまたがる使用量で算出する" do
+        expect_value = (23.67 * 140) + (23.88 * 160)
+        expect(tokyo_gas.usage_charge(300)).to eq expect_value
+      end
+
+      it "一番上の区分まで使用した算出をする" do
+        expect_value = (23.67 * 140) + (23.88 * 210) + (26.41 * 50)
+        expect(tokyo_gas.usage_charge(400)).to eq expect_value
+      end
+    end
+  end
+
+  describe "東京エナジーパートナー従量電灯B" do
+    let!(:tepco) { plan.find{ |plan| plan.provider_name == "東京電力エナジーパートナー" }}
+
+    describe "基本料金の算出が正しいこと" do
+      it "対応アンペアが存在する" do
+        expect(tepco.basic_charge(40)).to eq 1144
+      end
+
+      it "対応アンペアが存在しない" do
+        expect(tepco.basic_charge(100)).to eq nil
+      end
+    end
+
+    describe "従量課金料金の算出が正しいこと" do
+      it "1つの区分で収まる使用量で算出する" do
+        expect(tepco.usage_charge(100)).to eq (19.88 * 100)
+      end
+
+      it "2つ以上の区分にまたがる使用量で算出する" do
+        expect_value = (19.88 * 120) + (26.48 * 180)
+        expect(tepco.usage_charge(300)).to eq expect_value
+      end
+
+      it "一番上の区分まで使用した算出をする" do
+        expect_value = (19.88 * 120) + (26.48 * 180) + (30.57 * 100)
+        expect(tepco.usage_charge(400)).to eq expect_value
+      end
+    end
+  end
+
+  describe "Loop電気おうちプラン" do
+    let!(:loop) { plan.find{ |plan| plan.provider_name == "Looopでんき" }}
+
+    describe "基本料金の算出が正しいこと" do
+      it "対応アンペアが存在する" do
+        expect(loop.basic_charge(40)).to eq 0
+      end
+
+      it "対応アンペアが存在しない" do
+        expect(loop.basic_charge(100)).to eq nil
+      end
+    end
+
+    it "基本料金の算出が正しいこと" do
+      expect(loop.basic_charge(40)).to eq 0
+    end
+
+    describe "従量課金料金の算出が正しいこと(区分が1つのみ)" do
+      it "1つの区分だけで算出されること" do
+        expect(loop.usage_charge(500)).to eq (26.40 * 500)
+      end
+    end
+  end
+
+  describe "JXTGでんき従量電灯Bたっぷりプラン" do
+    let!(:jxtg) { plan.find{ |plan| plan.provider_name == "JXTGでんき" }}
+
+    describe "基本料金の算出が正しいこと" do
+      it "対応アンペアが存在する" do
+        expect(jxtg.basic_charge(50)).to eq 1430
+      end
+
+      it "対応アンペアが存在しない" do
+        expect(jxtg.basic_charge(100)).to eq nil
+      end
+    end
+
+    describe "従量課金料金の算出が正しいこと" do
+      it "1つの区分で収まる使用量で算出する" do
+        expect(jxtg.usage_charge(100)).to eq (19.88 * 100)
+      end
+
+      it "2つ以上の区分にまたがる使用量で算出する" do
+        expect_value = (19.88 * 120) + (26.48 * 180)
+        expect(jxtg.usage_charge(300)).to eq expect_value
+      end
+
+      it "一番上の区分まで使用した算出をする" do
+        expect_value = (19.88 * 120) + (26.48 * 180) + (25.08 * 300) + (26.15 * 50)
+        expect(jxtg.usage_charge(650)).to eq expect_value
+      end
+    end
+  end
+end
diff --git a/challengeA/tokiwa_takumi/spec/simulator_spec.rb b/challengeA/tokiwa_takumi/spec/simulator_spec.rb
new file mode 100644
index 000000000..33b9be3a6
--- /dev/null
+++ b/challengeA/tokiwa_takumi/spec/simulator_spec.rb
@@ -0,0 +1,33 @@
+require "spec_helper"
+
+RSpec.describe Simulator do
+  describe "simulatorの結果をが期待どおりであること" do
+    let!(:simulator) { Simulator.new(40, 300) }
+
+    it "simulator" do
+      expect(simulator.simulate.count).to eq 4
+      expect(simulator.simulate).to match_array [
+        {
+          "provider_name": "東京ガス",
+          "plan_name": "ずっともでんき１",
+          "price": 1144 + (23.67 * 140) + (23.88 * 160)
+        },
+        {
+          "provider_name": "JXTGでんき",
+          "plan_name": "従量電灯Bたっぷりプラン",
+          "price": 1144 + (19.88 * 120) + (26.48 * 180)
+        },
+        {
+          "provider_name": "Looopでんき",
+          "plan_name": "おうちプラン",
+          "price": (26.40 * 300)
+        },
+        {
+          "provider_name": "東京電力エナジーパートナー",
+          "plan_name": "従量電灯B",
+          "price": 1144 + (19.88 * 120) + (26.48 * 180)
+        }
+      ]
+    end
+  end
+end
diff --git a/challengeA/tokiwa_takumi/spec/spec_helper.rb b/challengeA/tokiwa_takumi/spec/spec_helper.rb
new file mode 100644
index 000000000..d592cedc7
--- /dev/null
+++ b/challengeA/tokiwa_takumi/spec/spec_helper.rb
@@ -0,0 +1,100 @@
+# This file was generated by the `rspec --init` command. Conventionally, all
+# specs live under a `spec` directory, which RSpec adds to the `$LOAD_PATH`.
+# The generated `.rspec` file contains `--require spec_helper` which will cause
+# this file to always be loaded, without a need to explicitly require it in any
+# files.
+#
+# Given that it is always loaded, you are encouraged to keep this file as
+# light-weight as possible. Requiring heavyweight dependencies from this file
+# will add to the boot time of your test suite on EVERY test run, even for an
+# individual file that may not need all of that loaded. Instead, consider making
+# a separate helper file that requires the additional dependencies and performs
+# the additional setup, and require it from the spec files that actually need
+# it.
+#
+# See http://rubydoc.info/gems/rspec-core/RSpec/Core/Configuration
+RSpec.configure do |config|
+  # rspec-expectations config goes here. You can use an alternate
+  # assertion/expectation library such as wrong or the stdlib/minitest
+  # assertions if you prefer.
+  config.expect_with :rspec do |expectations|
+    # This option will default to `true` in RSpec 4. It makes the `description`
+    # and `failure_message` of custom matchers include text for helper methods
+    # defined using `chain`, e.g.:
+    #     be_bigger_than(2).and_smaller_than(4).description
+    #     # => "be bigger than 2 and smaller than 4"
+    # ...rather than:
+    #     # => "be bigger than 2"
+    expectations.include_chain_clauses_in_custom_matcher_descriptions = true
+  end
+
+  # rspec-mocks config goes here. You can use an alternate test double
+  # library (such as bogus or mocha) by changing the `mock_with` option here.
+  config.mock_with :rspec do |mocks|
+    # Prevents you from mocking or stubbing a method that does not exist on
+    # a real object. This is generally recommended, and will default to
+    # `true` in RSpec 4.
+    mocks.verify_partial_doubles = true
+  end
+
+  # This option will default to `:apply_to_host_groups` in RSpec 4 (and will
+  # have no way to turn it off -- the option exists only for backwards
+  # compatibility in RSpec 3). It causes shared context metadata to be
+  # inherited by the metadata hash of host groups and examples, rather than
+  # triggering implicit auto-inclusion in groups with matching metadata.
+  config.shared_context_metadata_behavior = :apply_to_host_groups
+
+# The settings below are suggested to provide a good initial experience
+# with RSpec, but feel free to customize to your heart's content.
+  # This allows you to limit a spec run to individual examples or groups
+  # you care about by tagging them with `:focus` metadata. When nothing
+  # is tagged with `:focus`, all examples get run. RSpec also provides
+  # aliases for `it`, `describe`, and `context` that include `:focus`
+  # metadata: `fit`, `fdescribe` and `fcontext`, respectively.
+  config.filter_run_when_matching :focus
+
+  # Allows RSpec to persist some state between runs in order to support
+  # the `--only-failures` and `--next-failure` CLI options. We recommend
+  # you configure your source control system to ignore this file.
+  config.example_status_persistence_file_path = "spec/examples.txt"
+
+  # Limits the available syntax to the non-monkey patched syntax that is
+  # recommended. For more details, see:
+  #   - http://rspec.info/blog/2012/06/rspecs-new-expectation-syntax/
+  #   - http://www.teaisaweso.me/blog/2013/05/27/rspecs-new-message-expectation-syntax/
+  #   - http://rspec.info/blog/2014/05/notable-changes-in-rspec-3/#zero-monkey-patching-mode
+  config.disable_monkey_patching!
+
+  # This setting enables warnings. It's recommended, but in some cases may
+  # be too noisy due to issues in dependencies.
+  config.warnings = true
+
+  # Many RSpec users commonly either run the entire suite or an individual
+  # file, and it's useful to allow more verbose output when running an
+  # individual spec file.
+  if config.files_to_run.one?
+    # Use the documentation formatter for detailed output,
+    # unless a formatter has already been configured
+    # (e.g. via a command-line flag).
+    config.default_formatter = "doc"
+  end
+
+  # Print the 10 slowest examples and example groups at the
+  # end of the spec run, to help surface which specs are running
+  # particularly slow.
+  config.profile_examples = 10
+
+  # Run specs in random order to surface order dependencies. If you find an
+  # order dependency and want to debug it, you can fix the order by providing
+  # the seed, which is printed after each run.
+  #     --seed 1234
+  config.order = :random
+
+  # Seed global randomization in this process using the `--seed` CLI option.
+  # Setting this allows you to use `--seed` to deterministically reproduce
+  # test failures related to randomization by passing the same `--seed` value
+  # as the one that triggered the failure.
+  Kernel.srand config.seed
+
+  Dir[File.join(File.dirname(__FILE__), '../lib/*.rb')].each { |f| require f }
+end