diff --git a/core/field_checkbox.js b/core/field_checkbox.js
index 207b29f7f..df3509239 100644
--- a/core/field_checkbox.js
+++ b/core/field_checkbox.js
@@ -10,7 +10,8 @@
  */
 'use strict';
 
-goog.provide('Blockly.FieldCheckbox');
+goog.module('Blockly.FieldCheckbox');
+goog.module.declareLegacyNamespace();
 
 /** @suppress {extraRequire} */
 goog.require('Blockly.Events.BlockChange');
@@ -34,7 +35,7 @@ goog.require('Blockly.utils.object');
  * @extends {Blockly.Field}
  * @constructor
  */
-Blockly.FieldCheckbox = function(opt_value, opt_validator, opt_config) {
+const FieldCheckbox = function(opt_value, opt_validator, opt_config) {
   /**
    * Character for the check mark. Used to apply a different check mark
    * character to individual fields.
@@ -43,26 +44,26 @@ Blockly.FieldCheckbox = function(opt_value, opt_validator, opt_config) {
    */
   this.checkChar_ = null;
 
-  Blockly.FieldCheckbox.superClass_.constructor.call(
+  FieldCheckbox.superClass_.constructor.call(
       this, opt_value, opt_validator, opt_config);
 };
-Blockly.utils.object.inherits(Blockly.FieldCheckbox, Blockly.Field);
+Blockly.utils.object.inherits(FieldCheckbox, Blockly.Field);
 
 /**
  * The default value for this field.
  * @type {*}
  * @protected
  */
-Blockly.FieldCheckbox.prototype.DEFAULT_VALUE = false;
+FieldCheckbox.prototype.DEFAULT_VALUE = false;
 
 /**
  * Construct a FieldCheckbox from a JSON arg object.
  * @param {!Object} options A JSON object with options (checked).
- * @return {!Blockly.FieldCheckbox} The new field instance.
+ * @return {!FieldCheckbox} The new field instance.
  * @package
  * @nocollapse
  */
-Blockly.FieldCheckbox.fromJson = function(options) {
+FieldCheckbox.fromJson = function(options) {
   // `this` might be a subclass of FieldCheckbox if that class doesn't override
   // the static fromJson method.
   return new this(options['checked'], undefined, options);
@@ -73,19 +74,19 @@ Blockly.FieldCheckbox.fromJson = function(options) {
  * @type {string}
  * @const
  */
-Blockly.FieldCheckbox.CHECK_CHAR = '\u2713';
+FieldCheckbox.CHECK_CHAR = '\u2713';
 
 /**
  * Serializable fields are saved by the XML renderer, non-serializable fields
  * are not. Editable fields should also be serializable.
  * @type {boolean}
  */
-Blockly.FieldCheckbox.prototype.SERIALIZABLE = true;
+FieldCheckbox.prototype.SERIALIZABLE = true;
 
 /**
  * Mouse cursor style when over the hotspot that initiates editability.
  */
-Blockly.FieldCheckbox.prototype.CURSOR = 'default';
+FieldCheckbox.prototype.CURSOR = 'default';
 
 /**
  * Configure the field based on the given map of options.
@@ -93,8 +94,8 @@ Blockly.FieldCheckbox.prototype.CURSOR = 'default';
  * @protected
  * @override
  */
-Blockly.FieldCheckbox.prototype.configure_ = function(config) {
-  Blockly.FieldCheckbox.superClass_.configure_.call(this, config);
+FieldCheckbox.prototype.configure_ = function(config) {
+  FieldCheckbox.superClass_.configure_.call(this, config);
   if (config['checkCharacter']) {
     this.checkChar_ = config['checkCharacter'];
   }
@@ -104,8 +105,8 @@ Blockly.FieldCheckbox.prototype.configure_ = function(config) {
  * Create the block UI for this checkbox.
  * @package
  */
-Blockly.FieldCheckbox.prototype.initView = function() {
-  Blockly.FieldCheckbox.superClass_.initView.call(this);
+FieldCheckbox.prototype.initView = function() {
+  FieldCheckbox.superClass_.initView.call(this);
 
   Blockly.utils.dom.addClass(
       /** @type {!SVGTextElement} **/ (this.textElement_), 'blocklyCheckbox');
@@ -115,7 +116,7 @@ Blockly.FieldCheckbox.prototype.initView = function() {
 /**
  * @override
  */
-Blockly.FieldCheckbox.prototype.render_ = function() {
+FieldCheckbox.prototype.render_ = function() {
   if (this.textContent_) {
     this.textContent_.nodeValue = this.getDisplayText_();
   }
@@ -125,8 +126,8 @@ Blockly.FieldCheckbox.prototype.render_ = function() {
 /**
  * @override
  */
-Blockly.FieldCheckbox.prototype.getDisplayText_ = function() {
-  return this.checkChar_ || Blockly.FieldCheckbox.CHECK_CHAR;
+FieldCheckbox.prototype.getDisplayText_ = function() {
+  return this.checkChar_ || FieldCheckbox.CHECK_CHAR;
 };
 
 /**
@@ -134,7 +135,7 @@ Blockly.FieldCheckbox.prototype.getDisplayText_ = function() {
  * @param {?string} character The character to use for the check mark, or
  *    null to use the default.
  */
-Blockly.FieldCheckbox.prototype.setCheckCharacter = function(character) {
+FieldCheckbox.prototype.setCheckCharacter = function(character) {
   this.checkChar_ = character;
   this.forceRerender();
 };
@@ -143,7 +144,7 @@ Blockly.FieldCheckbox.prototype.setCheckCharacter = function(character) {
  * Toggle the state of the checkbox on click.
  * @protected
  */
-Blockly.FieldCheckbox.prototype.showEditor_ = function() {
+FieldCheckbox.prototype.showEditor_ = function() {
   this.setValue(!this.value_);
 };
 
@@ -153,7 +154,7 @@ Blockly.FieldCheckbox.prototype.showEditor_ = function() {
  * @return {?string} A valid value ('TRUE' or 'FALSE), or null if invalid.
  * @protected
  */
-Blockly.FieldCheckbox.prototype.doClassValidation_ = function(opt_newValue) {
+FieldCheckbox.prototype.doClassValidation_ = function(opt_newValue) {
   if (opt_newValue === true || opt_newValue === 'TRUE') {
     return 'TRUE';
   }
@@ -169,7 +170,7 @@ Blockly.FieldCheckbox.prototype.doClassValidation_ = function(opt_newValue) {
  * that this is a either 'TRUE' or 'FALSE'.
  * @protected
  */
-Blockly.FieldCheckbox.prototype.doValueUpdate_ = function(newValue) {
+FieldCheckbox.prototype.doValueUpdate_ = function(newValue) {
   this.value_ = this.convertValueToBool_(newValue);
   // Update visual.
   if (this.textElement_) {
@@ -181,7 +182,7 @@ Blockly.FieldCheckbox.prototype.doValueUpdate_ = function(newValue) {
  * Get the value of this field, either 'TRUE' or 'FALSE'.
  * @return {string} The value of this field.
  */
-Blockly.FieldCheckbox.prototype.getValue = function() {
+FieldCheckbox.prototype.getValue = function() {
   return this.value_ ? 'TRUE' : 'FALSE';
 };
 
@@ -189,7 +190,7 @@ Blockly.FieldCheckbox.prototype.getValue = function() {
  * Get the boolean value of this field.
  * @return {boolean} The boolean value of this field.
  */
-Blockly.FieldCheckbox.prototype.getValueBoolean = function() {
+FieldCheckbox.prototype.getValueBoolean = function() {
   return /** @type {boolean} */ (this.value_);
 };
 
@@ -198,7 +199,7 @@ Blockly.FieldCheckbox.prototype.getValueBoolean = function() {
  * @return {string} Text representing the value of this field
  *    ('true' or 'false').
  */
-Blockly.FieldCheckbox.prototype.getText = function() {
+FieldCheckbox.prototype.getText = function() {
   return String(this.convertValueToBool_(this.value_));
 };
 
@@ -211,7 +212,7 @@ Blockly.FieldCheckbox.prototype.getText = function() {
  * @return {boolean} The converted value.
  * @private
  */
-Blockly.FieldCheckbox.prototype.convertValueToBool_ = function(value) {
+FieldCheckbox.prototype.convertValueToBool_ = function(value) {
   if (typeof value == 'string') {
     return value == 'TRUE';
   } else {
@@ -219,4 +220,6 @@ Blockly.FieldCheckbox.prototype.convertValueToBool_ = function(value) {
   }
 };
 
-Blockly.fieldRegistry.register('field_checkbox', Blockly.FieldCheckbox);
+Blockly.fieldRegistry.register('field_checkbox', FieldCheckbox);
+
+exports = FieldCheckbox;
diff --git a/tests/deps.js b/tests/deps.js
index 979c58c74..d6e6163f8 100644
--- a/tests/deps.js
+++ b/tests/deps.js
@@ -50,7 +50,7 @@ goog.addDependency('../../core/events/ws_comment_events.js', ['Blockly.Events.Co
 goog.addDependency('../../core/extensions.js', ['Blockly.Extensions'], ['Blockly.utils'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/field.js', ['Blockly.Field'], ['Blockly.DropDownDiv', 'Blockly.Events', 'Blockly.Events.BlockChange', 'Blockly.Gesture', 'Blockly.IASTNodeLocationSvg', 'Blockly.IASTNodeLocationWithBlock', 'Blockly.IKeyboardAccessible', 'Blockly.IRegistrable', 'Blockly.MarkerManager', 'Blockly.Tooltip', 'Blockly.WidgetDiv', 'Blockly.browserEvents', 'Blockly.utils', 'Blockly.utils.Rect', 'Blockly.utils.Size', 'Blockly.utils.Svg', 'Blockly.utils.dom', 'Blockly.utils.style', 'Blockly.utils.userAgent'], {'lang': 'es5'});
 goog.addDependency('../../core/field_angle.js', ['Blockly.FieldAngle'], ['Blockly.Css', 'Blockly.DropDownDiv', 'Blockly.FieldTextInput', 'Blockly.WidgetDiv', 'Blockly.browserEvents', 'Blockly.fieldRegistry', 'Blockly.utils.KeyCodes', 'Blockly.utils.Svg', 'Blockly.utils.dom', 'Blockly.utils.math', 'Blockly.utils.object', 'Blockly.utils.userAgent']);
-goog.addDependency('../../core/field_checkbox.js', ['Blockly.FieldCheckbox'], ['Blockly.Events.BlockChange', 'Blockly.Field', 'Blockly.fieldRegistry', 'Blockly.utils.dom', 'Blockly.utils.object']);
+goog.addDependency('../../core/field_checkbox.js', ['Blockly.FieldCheckbox'], ['Blockly.Events.BlockChange', 'Blockly.Field', 'Blockly.fieldRegistry', 'Blockly.utils.dom', 'Blockly.utils.object'], {'lang': 'es6', 'module': 'goog'});
 goog.addDependency('../../core/field_colour.js', ['Blockly.FieldColour'], ['Blockly.Css', 'Blockly.DropDownDiv', 'Blockly.Events.BlockChange', 'Blockly.Field', 'Blockly.browserEvents', 'Blockly.fieldRegistry', 'Blockly.utils.IdGenerator', 'Blockly.utils.KeyCodes', 'Blockly.utils.Size', 'Blockly.utils.aria', 'Blockly.utils.colour', 'Blockly.utils.dom', 'Blockly.utils.object']);
 goog.addDependency('../../core/field_dropdown.js', ['Blockly.FieldDropdown'], ['Blockly.DropDownDiv', 'Blockly.Field', 'Blockly.Menu', 'Blockly.MenuItem', 'Blockly.fieldRegistry', 'Blockly.utils', 'Blockly.utils.Coordinate', 'Blockly.utils.Svg', 'Blockly.utils.aria', 'Blockly.utils.dom', 'Blockly.utils.object', 'Blockly.utils.string', 'Blockly.utils.userAgent']);
 goog.addDependency('../../core/field_image.js', ['Blockly.FieldImage'], ['Blockly.Field', 'Blockly.fieldRegistry', 'Blockly.utils', 'Blockly.utils.Size', 'Blockly.utils.Svg', 'Blockly.utils.dom', 'Blockly.utils.object']);