diff --git a/src/en/koushoku/AndroidManifest.xml b/src/en/koushoku/AndroidManifest.xml
new file mode 100644
index 000000000..20f02414a
--- /dev/null
+++ b/src/en/koushoku/AndroidManifest.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="eu.kanade.tachiyomi.extension">
+
+    <application>
+        <activity
+            android:name=".en.koushoku.KoushokuUrlActivity"
+            android:excludeFromRecents="true"
+            android:exported="true"
+            android:theme="@android:style/Theme.NoDisplay">
+            <intent-filter>
+                <action android:name="android.intent.action.VIEW" />
+
+                <category android:name="android.intent.category.DEFAULT" />
+                <category android:name="android.intent.category.BROWSABLE" />
+
+                <data
+                    android:host="koushoku.org"
+                    android:pathPattern="/archive/..*"
+                    android:scheme="https" />
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>
diff --git a/src/en/koushoku/build.gradle b/src/en/koushoku/build.gradle
new file mode 100644
index 000000000..8ada26b84
--- /dev/null
+++ b/src/en/koushoku/build.gradle
@@ -0,0 +1,16 @@
+apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
+
+ext {
+    extName = 'Koushoku'
+    pkgNameSuffix = 'en.koushoku'
+    extClass = '.Koushoku'
+    extVersionCode = 1
+    isNsfw = true
+}
+
+dependencies {
+    implementation project(':lib-ratelimit')
+}
+
+apply from: "$rootDir/common.gradle"
diff --git a/src/en/koushoku/res/mipmap-hdpi/ic_launcher.png b/src/en/koushoku/res/mipmap-hdpi/ic_launcher.png
new file mode 100644
index 000000000..0c9640875
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diff --git a/src/en/koushoku/res/mipmap-mdpi/ic_launcher.png b/src/en/koushoku/res/mipmap-mdpi/ic_launcher.png
new file mode 100644
index 000000000..67771ee44
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diff --git a/src/en/koushoku/res/mipmap-xhdpi/ic_launcher.png b/src/en/koushoku/res/mipmap-xhdpi/ic_launcher.png
new file mode 100644
index 000000000..8ef3c0ba1
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diff --git a/src/en/koushoku/res/mipmap-xxhdpi/ic_launcher.png b/src/en/koushoku/res/mipmap-xxhdpi/ic_launcher.png
new file mode 100644
index 000000000..ad2a381f2
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diff --git a/src/en/koushoku/res/mipmap-xxxhdpi/ic_launcher.png b/src/en/koushoku/res/mipmap-xxxhdpi/ic_launcher.png
new file mode 100644
index 000000000..3fd854742
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diff --git a/src/en/koushoku/res/web_hi_res_512.png b/src/en/koushoku/res/web_hi_res_512.png
new file mode 100644
index 000000000..39703f89f
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diff --git a/src/en/koushoku/src/eu/kanade/tachiyomi/extension/en/koushoku/Koushoku.kt b/src/en/koushoku/src/eu/kanade/tachiyomi/extension/en/koushoku/Koushoku.kt
new file mode 100644
index 000000000..3d86d41e8
--- /dev/null
+++ b/src/en/koushoku/src/eu/kanade/tachiyomi/extension/en/koushoku/Koushoku.kt
@@ -0,0 +1,202 @@
+package eu.kanade.tachiyomi.extension.en.koushoku
+
+import eu.kanade.tachiyomi.lib.ratelimit.RateLimitInterceptor
+import eu.kanade.tachiyomi.network.GET
+import eu.kanade.tachiyomi.network.asObservableSuccess
+import eu.kanade.tachiyomi.source.model.Filter
+import eu.kanade.tachiyomi.source.model.FilterList
+import eu.kanade.tachiyomi.source.model.MangasPage
+import eu.kanade.tachiyomi.source.model.Page
+import eu.kanade.tachiyomi.source.model.SChapter
+import eu.kanade.tachiyomi.source.model.SManga
+import eu.kanade.tachiyomi.source.online.ParsedHttpSource
+import eu.kanade.tachiyomi.util.asJsoup
+import okhttp3.HttpUrl.Companion.toHttpUrlOrNull
+import okhttp3.OkHttpClient
+import okhttp3.Request
+import okhttp3.Response
+import org.jsoup.nodes.Document
+import org.jsoup.nodes.Element
+import rx.Observable
+
+class Koushoku : ParsedHttpSource() {
+    companion object {
+        const val PREFIX_ID_SEARCH = "id:"
+
+        val archiveRegex = "/archive/(\\d+)".toRegex()
+        const val thumbnailSelector = ".thumbnail img"
+        const val magazinesSelector = ".metadata .magazines a"
+    }
+
+    override val baseUrl = "https://koushoku.org"
+    override val name = "Koushoku"
+    override val lang = "en"
+    override val supportsLatest = false
+
+    private val rateLimitInterceptor = RateLimitInterceptor(5)
+    override val client: OkHttpClient = network.cloudflareClient.newBuilder()
+        .addNetworkInterceptor(rateLimitInterceptor)
+        .build()
+
+    override fun latestUpdatesRequest(page: Int) = GET("$baseUrl/?page=$page", headers)
+    override fun latestUpdatesSelector() = "#archives.feed .entries > .entry"
+    override fun latestUpdatesNextPageSelector() = "#archives.feed .pagination .next"
+
+    override fun latestUpdatesFromElement(element: Element) = SManga.create().apply {
+        setUrlWithoutDomain(element.select("a").attr("href"))
+        title = element.select(".title").text()
+        thumbnail_url = "$baseUrl${element.select(thumbnailSelector).attr("src")}"
+    }
+
+    private fun searchMangaByIdRequest(id: String) = GET("$baseUrl/archive/$id", headers)
+
+    // taken from Tsumino ext
+    private fun searchMangaByIdParse(response: Response, id: String): MangasPage {
+        val details = mangaDetailsParse(response)
+        details.url = "/archive/$id"
+        return MangasPage(listOf(details), false)
+    }
+
+    // taken from Tsumino ext
+    override fun fetchSearchManga(
+        page: Int,
+        query: String,
+        filters: FilterList
+    ): Observable<MangasPage> {
+        return if (query.startsWith(PREFIX_ID_SEARCH)) {
+            val id = query.removePrefix(PREFIX_ID_SEARCH)
+            client.newCall(searchMangaByIdRequest(id)).asObservableSuccess()
+                .map { response -> searchMangaByIdParse(response, id) }
+        } else {
+            super.fetchSearchManga(page, query, filters)
+        }
+    }
+
+    override fun searchMangaRequest(page: Int, query: String, filters: FilterList): Request {
+        val url = "$baseUrl/search".toHttpUrlOrNull()!!.newBuilder()
+            .addQueryParameter("page", page.toString())
+            .addQueryParameter("q", query)
+
+        val filterList = if (filters.isEmpty()) getFilterList() else filters
+        filterList.findInstance<SortFilter>()?.let {
+            url.addQueryParameter("sort", it.toUriPart())
+        }
+        filterList.findInstance<OrderFilter>()?.let {
+            url.addQueryParameter("order", it.toUriPart())
+        }
+
+        return GET(url.toString(), headers)
+    }
+
+    override fun searchMangaSelector() = latestUpdatesSelector()
+    override fun searchMangaNextPageSelector() = latestUpdatesNextPageSelector()
+    override fun searchMangaFromElement(element: Element) = latestUpdatesFromElement(element)
+
+    override fun popularMangaRequest(page: Int) = latestUpdatesRequest(page)
+    override fun popularMangaSelector() = latestUpdatesSelector()
+    override fun popularMangaNextPageSelector() = latestUpdatesNextPageSelector()
+    override fun popularMangaFromElement(element: Element) = latestUpdatesFromElement(element)
+
+    override fun mangaDetailsParse(document: Document) = SManga.create().apply {
+        title = document.select(".metadata .title").text()
+        thumbnail_url = "$baseUrl${document.select(thumbnailSelector).attr("src")}"
+        artist = document.select(".metadata .artists a, .metadata .circles a")
+            .joinToString { it.text() }
+        author = artist
+        genre = document.select(".metadata .tags a, $magazinesSelector")
+            .ifEmpty { null }?.joinToString { it.text() }
+        description = getDesc(document)
+        status = SManga.COMPLETED
+    }
+
+    override fun chapterListRequest(manga: SManga) = GET("$baseUrl${manga.url}", headers)
+
+    override fun chapterListParse(response: Response): List<SChapter> {
+        val document = response.asJsoup()
+        return listOf(
+            SChapter.create().apply {
+                setUrlWithoutDomain(response.request.url.encodedPath)
+                name = "Chapter"
+                date_upload = document.select(".metadata .published td:nth-child(2)")
+                    .attr("data-unix").toLong() * 1000
+            }
+        )
+    }
+
+    override fun chapterFromElement(element: Element) =
+        throw UnsupportedOperationException("Not used")
+
+    override fun chapterListSelector() = throw UnsupportedOperationException("Not used")
+
+    override fun pageListRequest(chapter: SChapter) = GET("$baseUrl${chapter.url}/1")
+
+    override fun pageListParse(document: Document): List<Page> {
+        val totalPages = document.selectFirst(".total").text().toInt()
+        if (totalPages == 0)
+            throw UnsupportedOperationException("Error: Empty pages (try Webview)")
+
+        val id = archiveRegex.find(document.location())?.groups?.get(1)?.value
+        if (id.isNullOrEmpty())
+            throw UnsupportedOperationException("Error: Unknown archive id")
+
+        return (1..totalPages).map {
+            Page(it, "", "$baseUrl/data/$id/$it.jpg")
+        }
+    }
+
+    override fun imageUrlParse(document: Document) = throw UnsupportedOperationException("Not used")
+
+    override fun getFilterList() = FilterList(
+        SortFilter(),
+        OrderFilter()
+    )
+
+    private class SortFilter : UriPartFilter(
+        "Sort",
+        arrayOf(
+            Pair("Created Date", "created_at"),
+            Pair("ID", "id"),
+            Pair("Title", "title"),
+            Pair("Published Date", "published_at")
+        )
+    )
+
+    private class OrderFilter : UriPartFilter(
+        "Order",
+        arrayOf(
+            Pair("Descending", "desc"),
+            Pair("Ascending", "asc"),
+        )
+    )
+
+    // Taken from nhentai ext
+    private open class UriPartFilter(displayName: String, val vals: Array<Pair<String, String>>) :
+        Filter.Select<String>(displayName, vals.map { it.first }.toTypedArray()) {
+        fun toUriPart() = vals[state].second
+    }
+
+    // Taken from nhentai ext
+    private inline fun <reified T> Iterable<*>.findInstance() = find { it is T } as? T
+
+    private fun getDesc(document: Document) = buildString {
+        val magazines = document.select(magazinesSelector)
+        if (magazines.isNotEmpty()) {
+            append("Magazines: ")
+            append(magazines.joinToString { it.text() })
+            append("\n")
+        }
+
+        val parodies = document.select(".metadata .parodies a")
+        if (parodies.isNotEmpty()) {
+            append("Parodies: ")
+            append(parodies.joinToString { it.text() })
+            append("\n")
+        }
+
+        val pages = document.selectFirst(".metadata .pages td:nth-child(2)")
+        append("Pages: ").append(pages.text()).append("\n")
+
+        val size = document.selectFirst(".metadata .size td:nth-child(2)")
+        append("Size: ").append(size.text())
+    }
+}
diff --git a/src/en/koushoku/src/eu/kanade/tachiyomi/extension/en/koushoku/KoushokuUrlActivity.kt b/src/en/koushoku/src/eu/kanade/tachiyomi/extension/en/koushoku/KoushokuUrlActivity.kt
new file mode 100644
index 000000000..b3795b90f
--- /dev/null
+++ b/src/en/koushoku/src/eu/kanade/tachiyomi/extension/en/koushoku/KoushokuUrlActivity.kt
@@ -0,0 +1,38 @@
+package eu.kanade.tachiyomi.extension.en.koushoku
+
+import android.app.Activity
+import android.content.ActivityNotFoundException
+import android.content.Intent
+import android.os.Bundle
+import android.util.Log
+import kotlin.system.exitProcess
+
+/**
+ * Springboard that accepts https://koushoku.org/archive/xxxxx intents and redirects them to
+ * the main Tachiyomi process.
+ */
+class KoushokuUrlActivity : Activity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        val pathSegments = intent?.data?.pathSegments
+        if (pathSegments != null && pathSegments.size > 1) {
+            val id = pathSegments[1]
+            val mainIntent = Intent().apply {
+                action = "eu.kanade.tachiyomi.SEARCH"
+                putExtra("query", "${Koushoku.PREFIX_ID_SEARCH}$id")
+                putExtra("filter", packageName)
+            }
+
+            try {
+                startActivity(mainIntent)
+            } catch (e: ActivityNotFoundException) {
+                Log.e("KoushokuUrlActivity", e.toString())
+            }
+        } else {
+            Log.e("KoushokuUrlActivity", "could not parse uri from intent $intent")
+        }
+
+        finish()
+        exitProcess(0)
+    }
+}