diff --git a/Tests/KanaKanjiConverterModuleWithDefaultDictionaryTests/ExperimentalTests/InputGraph/ComposingTextV2.swift b/Tests/KanaKanjiConverterModuleWithDefaultDictionaryTests/ExperimentalTests/InputGraph/ComposingTextV2.swift
new file mode 100644
index 0000000..efaf74f
--- /dev/null
+++ b/Tests/KanaKanjiConverterModuleWithDefaultDictionaryTests/ExperimentalTests/InputGraph/ComposingTextV2.swift
@@ -0,0 +1,187 @@
+//
+//  ComposingTextV2.swift
+//  
+//
+//  Created by miwa on 2024/04/08.
+//
+
+import Foundation
+
+struct ComposingTextV2: Hashable, Sendable {
+    init() {
+        self.input = []
+        self.convertTarget = ""
+        self.cursorPosition = 0
+    }
+    
+    var input: [InputElement]
+    var convertTarget: String
+    var cursorPosition: Int
+
+    struct InputElement: Equatable, Hashable {
+        var value: Character
+        var inputStyle: InputGraphInputStyle.ID
+    }
+
+    mutating func append(_ element: InputElement) {
+        self.input.append(element)
+        self.convertTarget = Self.buildConvertTarget(input)
+    }
+
+    mutating func removeLast(_ k: Int = 1) {
+        let rest = self.convertTarget.dropLast(k)
+        typealias Item = (value: String, inputStyle: InputGraphInputStyle.ID)
+        var result: [Item] = []
+        var maxSuccess = (index: -1, string: "")
+        for elementIndex in input.indices {
+            let element = input[elementIndex]
+            if let last = result.last {
+                if last.inputStyle.isCompatible(with: element.inputStyle) {
+                    // 一旦inputStyleは継承することにする
+                    result[result.endIndex - 1].value.append(element.value)
+                } else {
+                    result.append((String(element.value), element.inputStyle))
+                }
+            } else {
+                result.append((String(element.value), element.inputStyle))
+            }
+
+            // 置換適用
+            var node = InputGraphInputStyle.init(from: element.inputStyle).replaceSuffixTree
+            let value = result[result.endIndex - 1].value
+            var maxMatch = (count: 0, replace: "")
+            var count = 0
+            var stack = Array(value)
+            while let c = stack.popLast(), let nextNode = node.find(key: c) {
+                count += 1
+                if let replace = nextNode.value {
+                    maxMatch = (count, replace)
+                }
+                node = nextNode
+            }
+            if maxMatch.count > 0 {
+                result[result.endIndex - 1].value.removeLast(maxMatch.count)
+                result[result.endIndex - 1].value.append(contentsOf: maxMatch.replace)
+            }
+            let current = result.reduce(into: "") { $0.append(contentsOf: $1.value) }
+            if rest.hasPrefix(current) {
+                maxSuccess = (elementIndex, current)
+            }
+        }
+        self.input = Array(self.input.prefix(maxSuccess.index + 1))
+        self.input.append(contentsOf: rest.dropFirst(maxSuccess.string.count).map { .init(value: $0, inputStyle: .none) })
+        self.convertTarget = String(rest)
+    }
+
+    static func buildConvertTarget(_ input: [InputElement]) -> String {
+        typealias Item = (value: String, inputStyle: InputGraphInputStyle.ID)
+        var result: [Item] = []
+        for element in input {
+            if let last = result.last {
+                if last.inputStyle.isCompatible(with: element.inputStyle) {
+                    // 一旦inputStyleは継承することにする
+                    result[result.endIndex - 1].value.append(element.value)
+                } else {
+                    result.append((String(element.value), element.inputStyle))
+                }
+            } else {
+                result.append((String(element.value), element.inputStyle))
+            }
+
+            // 置換適用
+            var node = InputGraphInputStyle.init(from: element.inputStyle).replaceSuffixTree
+            let value = result[result.endIndex - 1].value
+            var maxMatch = (count: 0, replace: "")
+            var count = 0
+            var stack = Array(value)
+            while let c = stack.popLast(), let nextNode = node.find(key: c) {
+                count += 1
+                if let replace = nextNode.value {
+                    maxMatch = (count, replace)
+                }
+                node = nextNode
+            }
+            if maxMatch.count > 0 {
+                result[result.endIndex - 1].value.removeLast(maxMatch.count)
+                result[result.endIndex - 1].value.append(contentsOf: maxMatch.replace)
+            }
+        }
+        return result.reduce(into: "") { $0.append(contentsOf: $1.value) }
+    }
+}
+
+
+import XCTest
+
+class ComposingTextV2Test: XCTestCase {
+    func testAppend() throws {
+        var c = ComposingTextV2()
+        c.append(.init(value: "a", inputStyle: .systemRomanKana))
+        XCTAssertEqual(c.convertTarget, "あ")
+        c.append(.init(value: "t", inputStyle: .systemRomanKana))
+        XCTAssertEqual(c.convertTarget, "あt")
+        c.append(.init(value: "t", inputStyle: .systemRomanKana))
+        XCTAssertEqual(c.convertTarget, "あっt")
+        c.append(.init(value: "a", inputStyle: .systemRomanKana))
+        XCTAssertEqual(c.convertTarget, "あった")
+    }
+    func testDelete_ata() throws {
+        var c = ComposingTextV2()
+        c.append(.init(value: "a", inputStyle: .systemRomanKana))
+        c.append(.init(value: "t", inputStyle: .systemRomanKana))
+        c.append(.init(value: "a", inputStyle: .systemRomanKana))
+        c.removeLast()
+        XCTAssertEqual(c.convertTarget, "あ")
+    }
+    func testDelete_asha() throws {
+        var c = ComposingTextV2()
+        c.append(.init(value: "a", inputStyle: .systemRomanKana))
+        c.append(.init(value: "s", inputStyle: .systemRomanKana))
+        c.append(.init(value: "h", inputStyle: .systemRomanKana))
+        c.append(.init(value: "a", inputStyle: .systemRomanKana))
+        c.removeLast()
+        XCTAssertEqual(c.convertTarget, "あし")
+        XCTAssertEqual(c.input.count, 2)
+        XCTAssertEqual(c.input[0], .init(value: "a", inputStyle: .systemRomanKana))
+        XCTAssertEqual(c.input[1], .init(value: "し", inputStyle: .none))
+    }
+    func testDelete_atta() throws {
+        var c = ComposingTextV2()
+        c.append(.init(value: "a", inputStyle: .systemRomanKana))
+        c.append(.init(value: "t", inputStyle: .systemRomanKana))
+        c.append(.init(value: "t", inputStyle: .systemRomanKana))
+        c.append(.init(value: "a", inputStyle: .systemRomanKana))
+        c.removeLast()
+        XCTAssertEqual(c.convertTarget, "あっ")
+        XCTAssertEqual(c.input.count, 2)
+        XCTAssertEqual(c.input[0], .init(value: "a", inputStyle: .systemRomanKana))
+        XCTAssertEqual(c.input[1], .init(value: "っ", inputStyle: .none))
+    }
+    func testDelete_aita() throws {
+        var c = ComposingTextV2()
+        c.append(.init(value: "a", inputStyle: .systemRomanKana))
+        c.append(.init(value: "i", inputStyle: .systemRomanKana))
+        c.append(.init(value: "t", inputStyle: .systemRomanKana))
+        c.append(.init(value: "a", inputStyle: .systemRomanKana))
+        c.removeLast()
+        XCTAssertEqual(c.convertTarget, "あい")
+        XCTAssertEqual(c.input.count, 2)
+        XCTAssertEqual(c.input[0], .init(value: "a", inputStyle: .systemRomanKana))
+        XCTAssertEqual(c.input[1], .init(value: "i", inputStyle: .systemRomanKana))
+    }
+    func testBuildConvertTarget() throws {
+        XCTAssertEqual(ComposingTextV2.buildConvertTarget([.init(value: "a", inputStyle: .systemRomanKana)]), "あ")
+        XCTAssertEqual(ComposingTextV2.buildConvertTarget([.init(value: "t", inputStyle: .systemRomanKana)]), "t")
+        XCTAssertEqual(
+            ComposingTextV2.buildConvertTarget(
+                [
+                    .init(value: "a", inputStyle: .systemRomanKana),
+                    .init(value: "t", inputStyle: .systemRomanKana),
+                    .init(value: "t", inputStyle: .systemRomanKana),
+                    .init(value: "a", inputStyle: .systemRomanKana)
+                ]
+            ),
+            "あった"
+        )
+    }
+}
diff --git a/Tests/KanaKanjiConverterModuleWithDefaultDictionaryTests/ExperimentalTests/InputGraph/InputGraphComponents.swift b/Tests/KanaKanjiConverterModuleWithDefaultDictionaryTests/ExperimentalTests/InputGraph/InputGraphComponents.swift
index ec63d2a..10a7a5d 100644
--- a/Tests/KanaKanjiConverterModuleWithDefaultDictionaryTests/ExperimentalTests/InputGraph/InputGraphComponents.swift
+++ b/Tests/KanaKanjiConverterModuleWithDefaultDictionaryTests/ExperimentalTests/InputGraph/InputGraphComponents.swift
@@ -56,6 +56,7 @@ struct InputGraphInputStyle: Identifiable {
         case .all: .all
         case .systemFlickDirect: .systemFlickDirect
         case .systemRomanKana: .systemRomanKana
+        case .none: .none
         default: fatalError("Unimplemented")
         }
     }
@@ -78,7 +79,8 @@ struct InputGraphInputStyle: Identifiable {
                 self = .systemRomanKana
             }
         }
-        static let all = Self(id: 0x00)
+        static let none = Self(id: 0x00)
+        static let all = Self(id: 0xFF)
         static let systemFlickDirect = Self(id: 0x01)
         static let systemRomanKana = Self(id: 0x02)
         var id: UInt8
@@ -94,6 +96,11 @@ struct InputGraphInputStyle: Identifiable {
             "ID(\(id))"
         }
     }
+    static let none: Self = Self(
+        id: .none,
+        replaceSuffixTree: ReplaceSuffixTree.Node(),
+        correctSuffixTree: CorrectSuffixTree.Node()
+    )
     static let all: Self = Self(
         id: .all,
         replaceSuffixTree: ReplaceSuffixTree.Node(),