diff --git a/kotlin/.gitignore b/kotlin/.gitignore
new file mode 100644
index 0000000..418c4b2
--- /dev/null
+++ b/kotlin/.gitignore
@@ -0,0 +1,55 @@
+.DS_Store
+.idea/shelf
+/android.tests.dependencies
+/confluence/target
+/dependencies/repo
+/dist
+/local
+/gh-pages
+/ideaSDK
+/clionSDK
+/android-studio/sdk
+out/
+/tmp
+workspace.xml
+*.versionsBackup
+/idea/testData/debugger/tinyApp/classes*
+/jps-plugin/testData/kannotator
+/js/js.translator/testData/out/
+/js/js.translator/testData/out-min/
+.gradle/
+build/
+!**/src/**/build
+!**/test/**/build
+*.iml
+!**/testData/**/*.iml
+.idea/libraries/Gradle*.xml
+.idea/libraries/Maven*.xml
+.idea/artifacts/PILL_*.xml
+.idea/artifacts/KotlinPlugin.xml
+.idea/modules
+.idea/runConfigurations/JPS_*.xml
+.idea/runConfigurations/PILL_*.xml
+.idea/libraries
+.idea/modules.xml
+.idea/gradle.xml
+.idea/compiler.xml
+.idea/inspectionProfiles/profiles_settings.xml
+.idea/.name
+.idea/artifacts/dist_auto_*
+.idea/artifacts/dist.xml
+.idea/artifacts/ideaPlugin.xml
+.idea/artifacts/kotlinc.xml
+.idea/artifacts/kotlin_compiler_jar.xml
+.idea/artifacts/kotlin_plugin_jar.xml
+.idea/artifacts/kotlin_jps_plugin_jar.xml
+.idea/artifacts/kotlin_daemon_client_jar.xml
+.idea/artifacts/kotlin_imports_dumper_compiler_plugin_jar.xml
+.idea/artifacts/kotlin_main_kts_jar.xml
+.idea/artifacts/kotlin_compiler_client_embeddable_jar.xml
+.idea/artifacts/kotlin_reflect_jar.xml
+kotlin-ultimate/
+node_modules/
+.rpt2_cache/
+libraries/tools/kotlin-test-nodejs-runner/lib/
+local.properties
diff --git a/kotlin/build.gradle b/kotlin/build.gradle
new file mode 100644
index 0000000..eb9cb70
--- /dev/null
+++ b/kotlin/build.gradle
@@ -0,0 +1,31 @@
+plugins {
+    id 'java'
+    id 'org.jetbrains.kotlin.jvm' version '1.3.50'
+}
+
+group 'com.kata'
+version '1.0-SNAPSHOT'
+
+sourceCompatibility = 1.8
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.3.1'
+    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.3.1'
+    testCompile("org.junit.jupiter:junit-jupiter-params:5.4.2")
+}
+
+test {
+    useJUnitPlatform()
+}
+
+compileKotlin {
+    kotlinOptions.jvmTarget = "1.8"
+}
+compileTestKotlin {
+    kotlinOptions.jvmTarget = "1.8"
+}
\ No newline at end of file
diff --git a/kotlin/gradle.properties b/kotlin/gradle.properties
new file mode 100644
index 0000000..29e08e8
--- /dev/null
+++ b/kotlin/gradle.properties
@@ -0,0 +1 @@
+kotlin.code.style=official
\ No newline at end of file
diff --git a/kotlin/gradle/wrapper/gradle-wrapper.jar b/kotlin/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..94336fc
Binary files /dev/null and b/kotlin/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/kotlin/gradle/wrapper/gradle-wrapper.properties b/kotlin/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..290541c
--- /dev/null
+++ b/kotlin/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.10.3-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/kotlin/gradlew b/kotlin/gradlew
new file mode 100755
index 0000000..cccdd3d
--- /dev/null
+++ b/kotlin/gradlew
@@ -0,0 +1,172 @@
+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"
diff --git a/kotlin/gradlew.bat b/kotlin/gradlew.bat
new file mode 100644
index 0000000..f955316
--- /dev/null
+++ b/kotlin/gradlew.bat
@@ -0,0 +1,84 @@
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/kotlin/settings.gradle b/kotlin/settings.gradle
new file mode 100644
index 0000000..d0714de
--- /dev/null
+++ b/kotlin/settings.gradle
@@ -0,0 +1,2 @@
+rootProject.name = 'kotlin'
+
diff --git a/kotlin/src/main/kotlin/Invoice.kt b/kotlin/src/main/kotlin/Invoice.kt
new file mode 100644
index 0000000..cf864f0
--- /dev/null
+++ b/kotlin/src/main/kotlin/Invoice.kt
@@ -0,0 +1 @@
+data class Invoice(val customer: String, val performances: List<Performance>)
diff --git a/kotlin/src/main/kotlin/Performance.kt b/kotlin/src/main/kotlin/Performance.kt
new file mode 100644
index 0000000..efd1ea2
--- /dev/null
+++ b/kotlin/src/main/kotlin/Performance.kt
@@ -0,0 +1 @@
+data class Performance(val playID: String, val audience: Int)
diff --git a/kotlin/src/main/kotlin/Play.kt b/kotlin/src/main/kotlin/Play.kt
new file mode 100644
index 0000000..7449e48
--- /dev/null
+++ b/kotlin/src/main/kotlin/Play.kt
@@ -0,0 +1 @@
+data class Play(val name: String, val type: String)
diff --git a/kotlin/src/main/kotlin/StatementPrinter.kt b/kotlin/src/main/kotlin/StatementPrinter.kt
new file mode 100644
index 0000000..db1e59e
--- /dev/null
+++ b/kotlin/src/main/kotlin/StatementPrinter.kt
@@ -0,0 +1,51 @@
+import java.text.NumberFormat
+import java.util.Locale
+import kotlin.math.floor
+import kotlin.math.max
+
+class StatementPrinter {
+
+    fun print(invoice: Invoice, plays: Map<String, Play>): String {
+        var totalAmount = 0
+        var volumeCredits = 0
+        var result = "Statement for ${invoice.customer}\n"
+
+        val frmt = NumberFormat.getCurrencyInstance(Locale.US)
+
+        for ((playID, audience) in invoice.performances) {
+            val play = plays[playID]
+            var thisAmount = 0
+
+            when (play?.type) {
+                "tragedy" -> {
+                    thisAmount = 40000
+                    if (audience > 30) {
+                        thisAmount += 1000 * (audience - 30)
+                    }
+                }
+                "comedy" -> {
+                    thisAmount = 30000
+                    if (audience > 20) {
+                        thisAmount += 10000 + 500 * (audience - 20)
+                    }
+                    thisAmount += 300 * audience
+                }
+                else -> throw Error("unknown type: {play.type}")
+            }
+
+            // add volume credits
+            volumeCredits += max(audience - 30, 0)
+            // add extra credit for every ten comedy attendees
+            if ("comedy" == play.type) volumeCredits += floor((audience / 5).toDouble()).toInt()
+
+            // print line for this order
+            result += "  ${play.name}: ${frmt.format((thisAmount / 100).toLong())} ($audience seats)\n"
+
+            totalAmount += thisAmount
+        }
+        result += "Amount owed is ${frmt.format((totalAmount / 100).toLong())}\n"
+        result += "You earned $volumeCredits credits\n"
+        return result
+    }
+
+}
diff --git a/kotlin/src/test/kotlin/StatementPrinterTests.kt b/kotlin/src/test/kotlin/StatementPrinterTests.kt
new file mode 100644
index 0000000..d54adab
--- /dev/null
+++ b/kotlin/src/test/kotlin/StatementPrinterTests.kt
@@ -0,0 +1,53 @@
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertThrows
+import org.junit.jupiter.api.Test
+
+class StatementPrinterTests {
+
+    @Test
+    internal fun exampleStatement() {
+        val expected = "Statement for BigCo\n" +
+                "  Hamlet: \$650.00 (55 seats)\n" +
+                "  As You Like It: \$580.00 (35 seats)\n" +
+                "  Othello: \$500.00 (40 seats)\n" +
+                "Amount owed is \$1,730.00\n" +
+                "You earned 47 credits\n"
+
+        val plays = mapOf(
+            "hamlet" to Play("Hamlet", "tragedy"),
+            "as-like" to Play("As You Like It", "comedy"),
+            "othello" to Play("Othello", "tragedy")
+        )
+
+        val invoice = Invoice(
+            "BigCo", listOf(
+                Performance("hamlet", 55),
+                Performance("as-like", 35),
+                Performance("othello", 40)
+            )
+        )
+
+        val statementPrinter = StatementPrinter()
+        val result = statementPrinter.print(invoice, plays)
+
+        assertEquals(expected, result)
+    }
+
+    @Test
+    internal fun statementWithNewPlayTypes() {
+        val plays = mapOf(
+            "henry-v" to Play("Henry V", "history"),
+            "as-like" to Play("As You Like It", "pastoral")
+        )
+
+        val invoice = Invoice(
+            "BigCo", listOf(
+                Performance("henry-v", 53),
+                Performance("as-like", 55)
+            )
+        )
+
+        val statementPrinter = StatementPrinter()
+        assertThrows(Error::class.java) { statementPrinter.print(invoice, plays) }
+    }
+}