diff --git a/packages/SwingSet/src/kernel/virtualObjectManager.js b/packages/SwingSet/src/kernel/virtualObjectManager.js
index b5a8782dfa0..0ed1dddcd91 100644
--- a/packages/SwingSet/src/kernel/virtualObjectManager.js
+++ b/packages/SwingSet/src/kernel/virtualObjectManager.js
@@ -1,7 +1,7 @@
 import { assert, details as d, quote as q } from '@agoric/assert';
 import { parseVatSlot } from '../parseVatSlots';
 
-const initializationInProgress = Symbol('initializing');
+const initializationsInProgress = new WeakSet();
 
 /**
  * Make a simple LRU cache of virtual object inner selves.
@@ -26,9 +26,9 @@ export function makeCache(size, fetch, store) {
   const cache = {
     makeRoom() {
       while (liveTable.size > size && lruTail) {
-        if (lruTail.rawData[initializationInProgress]) {
+        if (initializationsInProgress.has(lruTail.rawData)) {
           let refreshCount = 1;
-          while (lruTail.rawData[initializationInProgress]) {
+          while (initializationsInProgress.has(lruTail.rawData)) {
             if (refreshCount > size) {
               throw Error(`cache overflowed with objects being initialized`);
             }
@@ -37,7 +37,10 @@ export function makeCache(size, fetch, store) {
           }
         }
         liveTable.delete(lruTail.vobjID);
-        store(lruTail.vobjID, lruTail.rawData);
+        if (lruTail.dirty) {
+          store(lruTail.vobjID, lruTail.rawData);
+          lruTail.dirty = false;
+        }
         lruTail.rawData = null;
         if (lruTail.prev) {
           lruTail.prev.next = undefined;
@@ -115,7 +118,7 @@ export function makeCache(size, fetch, store) {
  * @param {*} m The vat's marshaler.
  * @param {number} cacheSize How many virtual objects this manager should cache
  *   in memory.
- * @returns {*} a new virtual object manager.
+ * @returns {Object} a new virtual object manager.
  *
  * The virtual object manager allows the creation of persistent objects that do
  * not need to occupy memory when they are not in use.  It provides four
@@ -382,7 +385,7 @@ export function makeVirtualObjectManager(
 
       function wrapData(target) {
         assert(
-          !target[initializationInProgress],
+          !initializationsInProgress.has(target),
           `object is still being initialized`,
         );
         for (const prop of Object.getOwnPropertyNames(innerSelf.rawData)) {
@@ -395,6 +398,7 @@ export function makeVirtualObjectManager(
               const serializedValue = m.serialize(value);
               ensureState(innerSelf);
               innerSelf.rawData[prop] = serializedValue;
+              innerSelf.dirty = true;
             },
           });
         }
@@ -402,24 +406,22 @@ export function makeVirtualObjectManager(
         harden(target);
       }
 
-      let representative;
+      let instanceKit;
       if (initializing) {
         innerSelf.wrapData = wrapData;
-        representative = instanceMaker(innerSelf.rawData);
+        instanceKit = harden(instanceMaker(innerSelf.rawData));
       } else {
         const activeData = {};
         wrapData(activeData);
-        representative = instanceMaker(activeData);
-        delete representative.initialize;
-        harden(representative);
+        instanceKit = harden(instanceMaker(activeData));
       }
       cache.remember(innerSelf);
-      valToSlotTable.set(representative, innerSelf.vobjID);
-      return representative;
+      valToSlotTable.set(instanceKit.self, innerSelf.vobjID);
+      return instanceKit;
     }
 
     function reanimate(vobjID) {
-      return makeRepresentative(cache.lookup(vobjID), false);
+      return makeRepresentative(cache.lookup(vobjID), false).self;
     }
     kindTable.set(kindID, reanimate);
 
@@ -428,20 +430,15 @@ export function makeVirtualObjectManager(
       nextInstanceID += 1;
 
       const initialData = {};
-      Object.defineProperty(initialData, initializationInProgress, {
-        configurable: true,
-        enumerable: false,
-        writeable: false,
-        value: true,
-      });
+      initializationsInProgress.add(initialData);
       const innerSelf = { vobjID, rawData: initialData };
-      const initialRepresentative = makeRepresentative(innerSelf, true);
-      const initialize = initialRepresentative.initialize;
-      if (initialize) {
-        delete initialRepresentative.initialize;
-        initialize(...args);
+      // prettier-ignore
+      const { self: initialRepresentative, init } =
+        makeRepresentative(innerSelf, true);
+      if (init) {
+        init(...args);
       }
-      delete initialData[initializationInProgress];
+      initializationsInProgress.delete(initialData);
       const rawData = {};
       for (const prop of Object.getOwnPropertyNames(initialData)) {
         try {
@@ -453,6 +450,7 @@ export function makeVirtualObjectManager(
       }
       innerSelf.rawData = rawData;
       innerSelf.wrapData(initialData);
+      innerSelf.dirty = true;
       return initialRepresentative;
     }
 
diff --git a/packages/SwingSet/test/virtualObjects/test-virtualObjectCache.js b/packages/SwingSet/test/virtualObjects/test-virtualObjectCache.js
index b6758c5953b..ed6c96195e2 100644
--- a/packages/SwingSet/test/virtualObjects/test-virtualObjectCache.js
+++ b/packages/SwingSet/test/virtualObjects/test-virtualObjectCache.js
@@ -37,6 +37,7 @@ function makeThing(n) {
   return {
     vobjID: `t${n}`,
     rawData: `thing #${n}`,
+    dirty: true,
   };
 }
 
@@ -71,6 +72,7 @@ test('cache overflow and refresh', t => {
 
   // lookup that has no effect
   things[0] = cache.lookup('t0'); // cache: t0, t2, t5, t4
+  things[0].dirty = true; // pretend we changed it
   t.is(things[0].rawData, 'thing #0');
   t.is(things[3].rawData, null);
   t.deepEqual(store.getLog(), [
@@ -100,7 +102,6 @@ test('cache overflow and refresh', t => {
     ['store', 't2', 'thing #2'],
     ['store', 't0', 'thing #0'],
     ['store', 't4', 'thing #4'],
-    ['store', 't1', 'thing #1'],
   ]);
   t.deepEqual(store.dump(), [
     ['t0', 'thing #0'],
@@ -114,16 +115,22 @@ test('cache overflow and refresh', t => {
   // verify that changes get written
   things[0] = cache.lookup('t0'); // cache: t0
   things[0].rawData = 'new thing #0';
+  things[0].dirty = true;
   things[1] = cache.lookup('t1'); // cache: t1, t0
   things[1].rawData = 'new thing #1';
+  things[1].dirty = true;
   things[2] = cache.lookup('t2'); // cache: t2, t1, t0
   things[2].rawData = 'new thing #2';
+  things[2].dirty = true;
   things[3] = cache.lookup('t3'); // cache: t3, t2, t1, t0
   things[3].rawData = 'new thing #3';
+  things[3].dirty = true;
   things[4] = cache.lookup('t4'); // cache: t4, t3, t2, t1
   things[4].rawData = 'new thing #4';
+  things[4].dirty = true;
   things[5] = cache.lookup('t5'); // cache: t5, t4, t3, t2
   things[5].rawData = 'new thing #5';
+  things[5].dirty = true;
   t.is(things[0].rawData, null);
   t.is(things[5].rawData, 'new thing #5');
   t.deepEqual(store.getLog(), [
diff --git a/packages/SwingSet/test/virtualObjects/test-virtualObjectManager.js b/packages/SwingSet/test/virtualObjects/test-virtualObjectManager.js
index 099df14cecf..62d1585a9e7 100644
--- a/packages/SwingSet/test/virtualObjects/test-virtualObjectManager.js
+++ b/packages/SwingSet/test/virtualObjects/test-virtualObjectManager.js
@@ -76,52 +76,56 @@ function makeAllTheStuff(cacheSize) {
 
 function makeThingInstance(state) {
   return {
-    initialize(label = 'thing', counter = 0) {
+    init(label = 'thing', counter = 0) {
       state.counter = counter;
       state.label = label;
       state.resetCounter = 0;
     },
-    inc() {
-      state.counter += 1;
-      return state.counter;
-    },
-    reset(newStart) {
-      state.counter = newStart;
-      state.resetCounter += 1;
-      return state.resetCounter;
-    },
-    relabel(newLabel) {
-      state.label = newLabel;
-    },
-    get() {
-      return state.counter;
-    },
-    describe() {
-      return `${state.label} counter has been reset ${state.resetCounter} times and is now ${state.counter}`;
+    self: {
+      inc() {
+        state.counter += 1;
+        return state.counter;
+      },
+      reset(newStart) {
+        state.counter = newStart;
+        state.resetCounter += 1;
+        return state.resetCounter;
+      },
+      relabel(newLabel) {
+        state.label = newLabel;
+      },
+      get() {
+        return state.counter;
+      },
+      describe() {
+        return `${state.label} counter has been reset ${state.resetCounter} times and is now ${state.counter}`;
+      },
     },
   };
 }
 
 function makeZotInstance(state) {
   return {
-    initialize(arbitrary = 47, name = 'Bob', tag = 'say what?') {
+    init(arbitrary = 47, name = 'Bob', tag = 'say what?') {
       state.arbitrary = arbitrary;
       state.name = name;
       state.tag = tag;
       state.count = 0;
     },
-    sayHello(msg) {
-      state.count += 1;
-      return `${msg} ${state.name}`;
-    },
-    rename(newName) {
-      state.name = newName;
-      state.count += 1;
-      return state.name;
-    },
-    getInfo() {
-      state.count += 1;
-      return `zot ${state.name} tag=${state.tag} count=${state.count} arbitrary=${state.arbitrary}`;
+    self: {
+      sayHello(msg) {
+        state.count += 1;
+        return `${msg} ${state.name}`;
+      },
+      rename(newName) {
+        state.name = newName;
+        state.count += 1;
+        return state.name;
+      },
+      getInfo() {
+        state.count += 1;
+        return `zot ${state.name} tag=${state.tag} count=${state.count} arbitrary=${state.arbitrary}`;
+      },
     },
   };
 }
diff --git a/packages/SwingSet/test/virtualObjects/vat-representative-bootstrap.js b/packages/SwingSet/test/virtualObjects/vat-representative-bootstrap.js
index c0694b0d203..65ee43de063 100644
--- a/packages/SwingSet/test/virtualObjects/vat-representative-bootstrap.js
+++ b/packages/SwingSet/test/virtualObjects/vat-representative-bootstrap.js
@@ -4,11 +4,12 @@ const stuff = makeWeakStore();
 let initialSelf;
 
 function makeThingInstance(state) {
+  function init(name) {
+    state.name = name;
+    // eslint-disable-next-line no-use-before-define
+    initialSelf = self;
+  }
   const self = {
-    initialize(name) {
-      state.name = name;
-      initialSelf = self;
-    },
     getName() {
       return state.name;
     },
@@ -19,24 +20,24 @@ function makeThingInstance(state) {
       return self;
     },
   };
-  return self;
+  return { init, self };
 }
 
 const thingMaker = makeKind(makeThingInstance);
 
 function makeZotInstance(state) {
+  function init(name, forceOverflow) {
+    state.name = name;
+    // enough instances to push me out of the cache
+    for (let i = 0; i < 5; i += 1) {
+      stuff.init(thingMaker(`${name}-subthing${i}`, 29));
+    }
+    if (forceOverflow) {
+      // eslint-disable-next-line no-use-before-define
+      zotMaker('recur', true);
+    }
+  }
   const self = {
-    initialize(name, forceOverflow) {
-      state.name = name;
-      // enough instances to push me out of the cache
-      for (let i = 0; i < 5; i += 1) {
-        stuff.init(thingMaker(`${name}-subthing${i}`, 29));
-      }
-      if (forceOverflow) {
-        // eslint-disable-next-line no-use-before-define
-        zotMaker('recur', true);
-      }
-    },
     getName() {
       return state.name;
     },
@@ -44,7 +45,7 @@ function makeZotInstance(state) {
       state.name = newName;
     },
   };
-  return self;
+  return { init, self };
 }
 
 const zotMaker = makeKind(makeZotInstance);
diff --git a/packages/swingset-runner/demo/vatStore1/vat-bob.js b/packages/swingset-runner/demo/vatStore1/vat-bob.js
index 51f43b7d7ae..00624f61e3e 100644
--- a/packages/swingset-runner/demo/vatStore1/vat-bob.js
+++ b/packages/swingset-runner/demo/vatStore1/vat-bob.js
@@ -3,32 +3,34 @@ const p = console.log;
 
 function makeThingInstance(state) {
   return {
-    initialize(label = 'thing', counter = 0) {
+    init(label = 'thing', counter = 0) {
       p(`@@@ thing.initialize(${label}, ${counter})`);
       state.counter = counter;
       state.label = label;
       state.resetCounter = 0;
     },
-    inc() {
-      state.counter += 1;
-      p(`#thing# ${state.label} inc() counter now ${state.counter}`);
-    },
-    reset(newStart) {
-      p(`#thing# ${state.label} reset(${newStart})`);
-      state.counter = newStart;
-      state.resetCounter += 1;
-    },
-    relabel(newLabel) {
-      p(`#thing# ${state.label} relabel(${newLabel})`);
-      state.label = newLabel;
-    },
-    get() {
-      p(`#thing# ${state.label} get()=>${state.counter}`);
-      return state.counter;
-    },
-    describe() {
-      p(`#thing# ${state.label} describe()`);
-      return `${state.label} counter has been reset ${state.resetCounter} times and is now ${state.counter}`;
+    self: {
+      inc() {
+        state.counter += 1;
+        p(`#thing# ${state.label} inc() counter now ${state.counter}`);
+      },
+      reset(newStart) {
+        p(`#thing# ${state.label} reset(${newStart})`);
+        state.counter = newStart;
+        state.resetCounter += 1;
+      },
+      relabel(newLabel) {
+        p(`#thing# ${state.label} relabel(${newLabel})`);
+        state.label = newLabel;
+      },
+      get() {
+        p(`#thing# ${state.label} get()=>${state.counter}`);
+        return state.counter;
+      },
+      describe() {
+        p(`#thing# ${state.label} describe()`);
+        return `${state.label} counter has been reset ${state.resetCounter} times and is now ${state.counter}`;
+      },
     },
   };
 }
@@ -37,26 +39,28 @@ const thingMaker = makeKind(makeThingInstance);
 
 function makeZotInstance(state) {
   return {
-    initialize(arbitrary = 47, name = 'Bob', tag = 'say what?') {
+    init(arbitrary = 47, name = 'Bob', tag = 'say what?') {
       p(`@@@ zot.initialize(${arbitrary}, ${name}, ${tag})`);
       state.arbitrary = arbitrary;
       state.name = name;
       state.tag = tag;
       state.count = 0;
     },
-    sayHello(msg) {
-      p(`#zot# ${msg} ${state.name}`);
-      state.count += 1;
-    },
-    rename(newName) {
-      p(`#zot# ${state.name} rename(${newName})`);
-      state.name = newName;
-      state.count += 1;
-    },
-    printInfo() {
-      // prettier-ignore
-      p(`#zot# ${state.name} tag=${state.tag} count=${state.count} arbitrary=${state.arbitrary}`);
-      state.count += 1;
+    self: {
+      sayHello(msg) {
+        p(`#zot# ${msg} ${state.name}`);
+        state.count += 1;
+      },
+      rename(newName) {
+        p(`#zot# ${state.name} rename(${newName})`);
+        state.name = newName;
+        state.count += 1;
+      },
+      printInfo() {
+        // prettier-ignore
+        p(`#zot# ${state.name} tag=${state.tag} count=${state.count} arbitrary=${state.arbitrary}`);
+        state.count += 1;
+      },
     },
   };
 }
diff --git a/packages/swingset-runner/demo/vatStore2/thingHolder.js b/packages/swingset-runner/demo/vatStore2/thingHolder.js
index f16af5e8733..7e718dc73bd 100644
--- a/packages/swingset-runner/demo/vatStore2/thingHolder.js
+++ b/packages/swingset-runner/demo/vatStore2/thingHolder.js
@@ -6,32 +6,34 @@ const p = console.log;
 function build(name) {
   function makeThingInstance(state) {
     return {
-      initialize(label, companion, companionName) {
+      init(label, companion, companionName) {
         p(`${name}'s thing ${label}: initialize ${companionName}`);
         state.label = label;
         state.companion = companion;
         state.companionName = companionName;
         state.count = 0;
       },
-      echo(message) {
-        state.count += 1;
-        E(state.companion).say(message);
-      },
-      async changePartner(newCompanion) {
-        state.count += 1;
-        state.companion = newCompanion;
-        const companionName = await E(newCompanion).getName();
-        state.companionName = companionName;
-        p(`${name}'s thing ${state.label}: changePartner ${companionName}`);
-      },
-      getLabel() {
-        const label = state.label;
-        p(`${name}'s thing ${label}: getLabel`);
-        state.count += 1;
-        return label;
-      },
-      report() {
-        p(`${name}'s thing ${state.label} invoked ${state.count} times`);
+      self: {
+        echo(message) {
+          state.count += 1;
+          E(state.companion).say(message);
+        },
+        async changePartner(newCompanion) {
+          state.count += 1;
+          state.companion = newCompanion;
+          const companionName = await E(newCompanion).getName();
+          state.companionName = companionName;
+          p(`${name}'s thing ${state.label}: changePartner ${companionName}`);
+        },
+        getLabel() {
+          const label = state.label;
+          p(`${name}'s thing ${label}: getLabel`);
+          state.count += 1;
+          return label;
+        },
+        report() {
+          p(`${name}'s thing ${state.label} invoked ${state.count} times`);
+        },
       },
     };
   }