diff --git a/convention-plugins/src/main/kotlin/root.publication.gradle.kts b/convention-plugins/src/main/kotlin/root.publication.gradle.kts
index 4a12397..afad449 100644
--- a/convention-plugins/src/main/kotlin/root.publication.gradle.kts
+++ b/convention-plugins/src/main/kotlin/root.publication.gradle.kts
@@ -3,7 +3,7 @@ plugins {
 }
 object Conf {
     const val GROUP = "net.kigawa"
-    const val VERSION = "2.1.0"
+    const val VERSION = "3.1.0"
 }
 
 group = Conf.GROUP
diff --git a/hakate/src/commonMain/kotlin/net/kigawa/hakate/api/multi/MultiValue2.kt b/hakate/src/commonMain/kotlin/net/kigawa/hakate/api/multi/MultiValue2.kt
new file mode 100644
index 0000000..2e84958
--- /dev/null
+++ b/hakate/src/commonMain/kotlin/net/kigawa/hakate/api/multi/MultiValue2.kt
@@ -0,0 +1,9 @@
+package net.kigawa.hakate.api.multi
+
+import net.kigawa.hakate.api.state.State
+
+fun <T, U> mergeState(state1: State<T>, state2: State<U>): State<MultiValue2<T, U>> {
+    return state1.merge(state2) { a, b -> MultiValue2(a, b) }
+}
+
+data class MultiValue2<T, U>(val first: T, val second: U)
\ No newline at end of file
diff --git a/hakate/src/commonMain/kotlin/net/kigawa/hakate/api/multi/MultiValue3.kt b/hakate/src/commonMain/kotlin/net/kigawa/hakate/api/multi/MultiValue3.kt
new file mode 100644
index 0000000..09b72de
--- /dev/null
+++ b/hakate/src/commonMain/kotlin/net/kigawa/hakate/api/multi/MultiValue3.kt
@@ -0,0 +1,14 @@
+package net.kigawa.hakate.api.multi
+
+import net.kigawa.hakate.api.state.State
+
+@Suppress("unused")
+fun <T, U, V> mergeState(state1: State<T>, state2: State<U>, state3: State<V>): State<MultiValue3<T, U, V>> {
+    return mergeState(state1, state2).merge(state3)
+}
+
+fun <T, U, V> State<MultiValue2<T, U>>.merge(state3: State<V>): State<MultiValue3<T, U, V>> {
+    return merge(state3) { a, b -> MultiValue3(a.first, a.second, b) }
+}
+
+data class MultiValue3<T, U, V>(val first: T, val second: U, val third: V)
\ No newline at end of file
diff --git a/hakate/src/commonMain/kotlin/net/kigawa/hakate/api/state/State.kt b/hakate/src/commonMain/kotlin/net/kigawa/hakate/api/state/State.kt
index 540a4ee..40c1067 100644
--- a/hakate/src/commonMain/kotlin/net/kigawa/hakate/api/state/State.kt
+++ b/hakate/src/commonMain/kotlin/net/kigawa/hakate/api/state/State.kt
@@ -2,7 +2,9 @@ package net.kigawa.hakate.api.state
 
 import kotlinx.coroutines.Job
 
+@Suppress("unused")
 interface State<T> {
+    val stateContext: StateContext
     fun collect(context: StateContext, block: suspend StateContext.(value: T) -> Unit): Job
     fun <R> collect(
         context: StateContext, defaultValue: R, block: suspend StateContext.(value: T, prev: R) -> R,
@@ -20,4 +22,5 @@ interface State<T> {
 
     fun <R> child(block: (T) -> R): State<R>
     fun currentValue(): T
+    fun <U, R> merge(state: State<U>, block: (first: T, second: U) -> R): State<R>
 }
diff --git a/hakate/src/commonMain/kotlin/net/kigawa/hakate/api/state/StateContext.kt b/hakate/src/commonMain/kotlin/net/kigawa/hakate/api/state/StateContext.kt
index aa8a172..fce27e4 100644
--- a/hakate/src/commonMain/kotlin/net/kigawa/hakate/api/state/StateContext.kt
+++ b/hakate/src/commonMain/kotlin/net/kigawa/hakate/api/state/StateContext.kt
@@ -2,9 +2,10 @@ package net.kigawa.hakate.api.state
 
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Job
+import net.kigawa.hakate.impl.state.MergedStateContextImpl
 
 interface StateContext {
-    val coroutineScope: CoroutineScope
+    fun launch(block: suspend CoroutineScope.() -> Unit): Job
     fun dispatcher(): StateDispatcher
     fun dispatch(block: suspend StateContext.() -> Unit): Job
     fun <T, R> State<T>.collect(defaultValue: R, block: suspend StateContext.(value: T, prev: R) -> R) =
@@ -14,4 +15,7 @@ interface StateContext {
         this.collect(this@StateContext, block)
 
     fun cancel()
+    fun merge(other: StateContext): StateContext {
+        return MergedStateContextImpl(this, other)
+    }
 }
\ No newline at end of file
diff --git a/hakate/src/commonMain/kotlin/net/kigawa/hakate/impl/state/MergedStateContextImpl.kt b/hakate/src/commonMain/kotlin/net/kigawa/hakate/impl/state/MergedStateContextImpl.kt
new file mode 100644
index 0000000..88ba43c
--- /dev/null
+++ b/hakate/src/commonMain/kotlin/net/kigawa/hakate/impl/state/MergedStateContextImpl.kt
@@ -0,0 +1,40 @@
+package net.kigawa.hakate.impl.state
+
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.launch
+import kotlinx.coroutines.withContext
+import net.kigawa.hakate.api.state.StateContext
+import net.kigawa.hakate.api.state.StateDispatcher
+import net.kigawa.hakate.impl.Utl.suspendApply
+
+class MergedStateContextImpl(
+    private val first: StateContext,
+    private val second: StateContext,
+) : StateContext {
+    override fun launch(block: suspend CoroutineScope.() -> Unit): Job {
+        return first.launch {
+            val f = this
+            second.launch {
+                val s = this
+                f.launch { withContext(s.coroutineContext) { block() } }
+            }
+        }
+    }
+
+    override fun dispatcher(): StateDispatcher = first.dispatcher()
+    override fun dispatch(
+        block: suspend StateContext.() -> Unit,
+    ): Job {
+        return launch {
+            StateContextImpl(dispatcher(), this@launch).suspendApply {
+                block()
+            }
+        }
+    }
+
+    override fun cancel() {
+        first.cancel()
+        second.cancel()
+    }
+}
\ No newline at end of file
diff --git a/hakate/src/commonMain/kotlin/net/kigawa/hakate/impl/state/StateContextImpl.kt b/hakate/src/commonMain/kotlin/net/kigawa/hakate/impl/state/StateContextImpl.kt
index 01e6d27..99d7ee3 100644
--- a/hakate/src/commonMain/kotlin/net/kigawa/hakate/impl/state/StateContextImpl.kt
+++ b/hakate/src/commonMain/kotlin/net/kigawa/hakate/impl/state/StateContextImpl.kt
@@ -10,13 +10,17 @@ import net.kigawa.hakate.impl.Utl.suspendApply
 
 class StateContextImpl(
     private val dispatcher: StateDispatcher,
-    override val coroutineScope: CoroutineScope,
+    val coroutineScope: CoroutineScope,
 ) : StateContext {
+    override fun launch(block: suspend CoroutineScope.() -> Unit): Job {
+        return coroutineScope.launch(block = block)
+    }
+
     override fun dispatcher(): StateDispatcher = dispatcher
     override fun dispatch(
         block: suspend StateContext.() -> Unit,
     ): Job {
-        return coroutineScope.launch {
+        return launch {
             StateContextImpl(dispatcher, this@launch).suspendApply {
                 block()
             }
diff --git a/hakate/src/commonMain/kotlin/net/kigawa/hakate/impl/state/StateImpl.kt b/hakate/src/commonMain/kotlin/net/kigawa/hakate/impl/state/StateImpl.kt
index c134509..bbbcfcc 100644
--- a/hakate/src/commonMain/kotlin/net/kigawa/hakate/impl/state/StateImpl.kt
+++ b/hakate/src/commonMain/kotlin/net/kigawa/hakate/impl/state/StateImpl.kt
@@ -8,7 +8,7 @@ import net.kigawa.hakate.api.state.StateContext
 
 class StateImpl<T>(
     defaultValue: T,
-    private val stateContext: StateContext,
+    override val stateContext: StateContext,
 ) : MutableState<T> {
     private val flow = MutableStateFlow<T>(defaultValue)
     override fun collect(
@@ -45,5 +45,17 @@ class StateImpl<T>(
     }
 
     override fun currentValue(): T = flow.value
+    override fun <U, R> merge(
+        state: State<U>, block: (T, U) -> R,
+    ): State<R> {
+        val mergedContext = stateContext.merge(state.stateContext)
+        val newState = StateImpl(block(currentValue(), state.currentValue()), mergedContext)
+        collect(mergedContext) { v1 ->
+            state.collect(mergedContext) { v2 ->
+                newState.set(block(v1, v2))
+            }
+        }
+        return newState
+    }
 
 }
\ No newline at end of file
diff --git a/hakate/src/commonTest/kotlin/net/kigawa/hakate/api/state/StateTest.kt b/hakate/src/commonTest/kotlin/net/kigawa/hakate/api/state/StateTest.kt
index 65d46ac..735de63 100644
--- a/hakate/src/commonTest/kotlin/net/kigawa/hakate/api/state/StateTest.kt
+++ b/hakate/src/commonTest/kotlin/net/kigawa/hakate/api/state/StateTest.kt
@@ -54,8 +54,8 @@ class StateTest : StateTestBase() {
         isSet = false
         state.set(next)
 
-//        waitStateSet { isSet }
-//        assertEquals("$next-child", value)
+        waitStateSet { isSet }
+        assertEquals("$next-child", value)
     }
 
 }