diff --git a/README.md b/README.md
index e1c282e..b3d8979 100644
--- a/README.md
+++ b/README.md
@@ -118,6 +118,11 @@ book or page is placed on it; this in-world interaction has no JEI guide.
 With Create installed, Crystal Blocks and Book Receptacles have an optional Ponder scene
 showing crystal-frame construction, book activation, and a parrot crossing the portal. Use the Ponder shortcut
 while hovering either item; Rivencraft does not require Create to run.
+Crystal frames may stand vertically or lie flat: a 3×3 Crystal Block ring with
+an empty center forms a horizontal portal when a Book Receptacle is attached to
+the top or underside of one of its blocks. Insert a bound Linking or Descriptive
+Book to activate it; the book remains visible on the receptacle. A Linking Book aimed at its
+own dimension still opens a visual portal, but travel requires Intra Linking.
 
 Craft a Book Binder from three iron ingots and five planks. Put leather or an
 empty Notebook in the left cover slot. Enter a title, then place a Link Panel
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diff --git a/dev images/book receptical.png b/dev images/book receptical.png
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diff --git a/gradle.properties b/gradle.properties
index 5fea858..94e38b2 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -36,7 +36,7 @@ mod_name=Rivencraft
 # The license of the mod. Review your options at https://choosealicense.com/. All Rights Reserved is the default.
 mod_license=LGPL-3.0-or-later
 # The mod version. Rivencraft uses the x.y.z.b policy documented in README.md.
-mod_version=0.6.7.3
+mod_version=0.6.8.4
 immersive_portals_version=6.0.7
 terrablender_version=4.1.0.8
 serene_seasons_version_id=pHEgQQUE
diff --git a/src/main/java/net/dnorberg/rivencraft/block/BookReceptacleBlock.java b/src/main/java/net/dnorberg/rivencraft/block/BookReceptacleBlock.java
index 9269fa0..a6ccf71 100644
--- a/src/main/java/net/dnorberg/rivencraft/block/BookReceptacleBlock.java
+++ b/src/main/java/net/dnorberg/rivencraft/block/BookReceptacleBlock.java
@@ -77,7 +77,7 @@ public final class BookReceptacleBlock extends BaseEntityBlock {
     }
     @Override public BlockState getStateForPlacement(BlockPlaceContext context) {
         Direction face = context.getClickedFace();
-        if (face == Direction.DOWN || !context.getLevel().getBlockState(
+        if (!context.getLevel().getBlockState(
                 context.getClickedPos().relative(face.getOpposite())).is(ModBlocks.CRYSTAL_BLOCK.get())) return null;
         return defaultBlockState().setValue(FACING, face);
     }
diff --git a/src/main/java/net/dnorberg/rivencraft/client/BookReceptacleRenderer.java b/src/main/java/net/dnorberg/rivencraft/client/BookReceptacleRenderer.java
new file mode 100644
index 0000000..ebe98d5
--- /dev/null
+++ b/src/main/java/net/dnorberg/rivencraft/client/BookReceptacleRenderer.java
@@ -0,0 +1,67 @@
+package net.dnorberg.rivencraft.client;
+
+import com.mojang.blaze3d.vertex.PoseStack;
+import com.mojang.blaze3d.vertex.VertexConsumer;
+import com.mojang.math.Axis;
+import net.dnorberg.rivencraft.block.BookReceptacleBlock;
+import net.dnorberg.rivencraft.block.entity.BookReceptacleBlockEntity;
+import net.dnorberg.rivencraft.registry.ModItems;
+import net.minecraft.client.model.BookModel;
+import net.minecraft.client.model.geom.ModelLayers;
+import net.minecraft.client.renderer.MultiBufferSource;
+import net.minecraft.client.renderer.RenderType;
+import net.minecraft.client.renderer.blockentity.BlockEntityRenderer;
+import net.minecraft.client.renderer.blockentity.BlockEntityRendererProvider;
+import net.minecraft.core.Direction;
+import net.minecraft.resources.ResourceLocation;
+
+/** Legacy's almost-closed book, oriented to the receptacle's mounting face. */
+public final class BookReceptacleRenderer implements BlockEntityRenderer<BookReceptacleBlockEntity> {
+    private static final ResourceLocation LINKING_TEXTURE = ResourceLocation.fromNamespaceAndPath(
+            "rivencraft", "textures/entity/linking_book.png");
+    private static final ResourceLocation DESCRIPTIVE_TEXTURE = ResourceLocation.fromNamespaceAndPath(
+            "rivencraft", "textures/entity/descriptive_book.png");
+    private final BookModel model;
+
+    public BookReceptacleRenderer(BlockEntityRendererProvider.Context context) {
+        model = new BookModel(context.bakeLayer(ModelLayers.BOOK));
+    }
+
+    @Override
+    public void render(BookReceptacleBlockEntity receptacle, float partialTick, PoseStack poseStack,
+                       MultiBufferSource buffers, int packedLight, int packedOverlay) {
+        if (receptacle.getBook().isEmpty()) return;
+
+        poseStack.pushPose();
+        poseStack.translate(0.5, 0.5, 0.5);
+        Direction facing = receptacle.getBlockState().getValue(BookReceptacleBlock.FACING);
+        switch (facing) {
+            case UP -> {
+                // Rotate the whole assembled top-mounted receptacle/book pair
+                // around the block center, matching the x=90 block model.
+                poseStack.mulPose(Axis.ZP.rotationDegrees(180));
+                poseStack.mulPose(Axis.XP.rotationDegrees(-90));
+                poseStack.mulPose(Axis.YP.rotationDegrees(90));
+                // Preserve the local half-turn that seats the book in its slot.
+                poseStack.mulPose(Axis.ZP.rotationDegrees(180));
+            }
+            case DOWN -> {
+                // The ceiling-mounted model is the inverted top assembly.
+                poseStack.mulPose(Axis.XP.rotationDegrees(-90));
+                poseStack.mulPose(Axis.YP.rotationDegrees(90));
+                poseStack.mulPose(Axis.ZP.rotationDegrees(180));
+            }
+            case NORTH -> poseStack.mulPose(Axis.YP.rotationDegrees(-90));
+            case SOUTH -> poseStack.mulPose(Axis.YP.rotationDegrees(90));
+            case EAST -> poseStack.mulPose(Axis.YP.rotationDegrees(180));
+            case WEST -> { }
+        }
+        poseStack.scale(0.8F, 0.8F, 0.8F);
+        model.setupAnim(0.0F, 0.1F, 0.1F, 0.005F);
+        ResourceLocation texture = receptacle.getBook().is(ModItems.DESCRIPTIVE_BOOK.get())
+                ? DESCRIPTIVE_TEXTURE : LINKING_TEXTURE;
+        VertexConsumer vertices = buffers.getBuffer(RenderType.entitySolid(texture));
+        model.render(poseStack, vertices, packedLight, packedOverlay, -1);
+        poseStack.popPose();
+    }
+}
diff --git a/src/main/java/net/dnorberg/rivencraft/client/ClientEvents.java b/src/main/java/net/dnorberg/rivencraft/client/ClientEvents.java
index 2d5ff31..94d4b99 100644
--- a/src/main/java/net/dnorberg/rivencraft/client/ClientEvents.java
+++ b/src/main/java/net/dnorberg/rivencraft/client/ClientEvents.java
@@ -38,6 +38,7 @@ public final class ClientEvents {
     public static void registerRenderers(EntityRenderersEvent.RegisterRenderers event) {
         event.registerEntityRenderer(ModEntities.DROPPED_BOOK.get(), DroppedBookRenderer::new);
         event.registerBlockEntityRenderer(ModBlockEntities.BOOK_STAND.get(), BookStandRenderer::new);
+        event.registerBlockEntityRenderer(ModBlockEntities.BOOK_RECEPTACLE.get(), BookReceptacleRenderer::new);
         event.registerBlockEntityRenderer(ModBlockEntities.WRITING_DESK.get(), WritingDeskRenderer::new);
         event.registerBlockEntityRenderer(ModBlockEntities.STAR_FISSURE.get(), StarFissureRenderer::new);
     }
diff --git a/src/main/java/net/dnorberg/rivencraft/gametest/CrystalPortalGameTests.java b/src/main/java/net/dnorberg/rivencraft/gametest/CrystalPortalGameTests.java
index ba6ae63..73a61eb 100644
--- a/src/main/java/net/dnorberg/rivencraft/gametest/CrystalPortalGameTests.java
+++ b/src/main/java/net/dnorberg/rivencraft/gametest/CrystalPortalGameTests.java
@@ -6,6 +6,9 @@ import net.dnorberg.rivencraft.block.CrystalPortalBlock;
 import net.dnorberg.rivencraft.block.entity.BookReceptacleBlockEntity;
 import net.dnorberg.rivencraft.block.entity.CrystalPortalBlockEntity;
 import net.dnorberg.rivencraft.book.LinkTarget;
+import net.dnorberg.rivencraft.book.LinkProperties;
+import net.dnorberg.rivencraft.book.LinkingService;
+import net.dnorberg.rivencraft.registry.ModDataComponents;
 import net.dnorberg.rivencraft.portal.CrystalPortalNetwork;
 import net.dnorberg.rivencraft.portal.CrystalPortalSurfaces;
 import net.dnorberg.rivencraft.portal.PortalTravelCooldown;
@@ -19,7 +22,11 @@ import net.minecraft.gametest.framework.GameTestHelper;
 import net.minecraft.nbt.CompoundTag;
 import net.minecraft.server.level.ServerLevel;
 import net.minecraft.world.item.ItemStack;
+import net.minecraft.world.InteractionHand;
+import net.minecraft.world.item.context.BlockPlaceContext;
 import net.minecraft.world.level.block.Blocks;
+import net.minecraft.world.phys.BlockHitResult;
+import net.minecraft.world.phys.Vec3;
 import net.neoforged.neoforge.gametest.GameTestHolder;
 import net.neoforged.neoforge.gametest.PrefixGameTestTemplate;
 
@@ -154,13 +161,54 @@ public final class CrystalPortalGameTests {
         BlockPos holderPos = helper.absolutePos(new BlockPos(0, 2, 1));
         level.setBlock(holderPos, ModBlocks.BOOK_RECEPTACLE.get().defaultBlockState()
                 .setValue(BookReceptacleBlock.FACING, Direction.UP), 3);
-        ((BookReceptacleBlockEntity) level.getBlockEntity(holderPos))
-                .setBook(new ItemStack(ModItems.LINKING_BOOK.get()));
+        LinkTarget destination = new LinkTarget(GlobalPos.of(level.dimension(), centerTarget(helper)), 0, 0);
+        ItemStack book = new ItemStack(ModItems.LINKING_BOOK.get());
+        book.set(ModDataComponents.LINK_TARGET.get(), destination);
+        BookReceptacleBlockEntity holder = (BookReceptacleBlockEntity) level.getBlockEntity(holderPos);
+        holder.setBook(book);
+        holder.setDestination(destination);
         helper.assertTrue(CrystalPortalNetwork.activate(level, holderPos, planLoaded(level, holderPos)),
                 "The horizontal crystal opening must activate");
         helper.assertValueEqual(level.getBlockState(helper.absolutePos(new BlockPos(1, 1, 1)))
                 .getValue(CrystalPortalBlock.AXIS), Direction.Axis.Y,
                 "The fallback surface must face up and down");
+        helper.assertValueEqual(CrystalPortalSurfaces.group(level, planLoaded(level, holderPos)).getFirst().normal(),
+                Direction.UP, "The horizontal opening must provide an upward-facing destination view");
+        var player = helper.makeMockServerPlayerInLevel();
+        helper.assertValueEqual(LinkingService.travelPortal(player, destination, LinkProperties.NONE),
+                LinkingService.LinkResult.INTRA_LINKING_REQUIRED,
+                "A normal book may show a portal but must not link within its own dimension");
+        helper.assertTrue(level.getBlockState(helper.absolutePos(new BlockPos(1, 1, 1)))
+                        .is(ModBlocks.CRYSTAL_PORTAL.get()) && !holder.getBook().isEmpty(),
+                "Rejected intra-link travel must leave the visual portal and its book intact");
+        helper.succeed();
+    }
+
+    @GameTest(template = "empty")
+    public static void undersideReceptaclePlacesAndActivatesHorizontalFrame(GameTestHelper helper) {
+        var level = helper.getLevel();
+        for (int x = 0; x < 3; x++) for (int z = 0; z < 3; z++) {
+            level.setBlock(helper.absolutePos(new BlockPos(x, 2, z)),
+                    x == 1 && z == 1 ? Blocks.AIR.defaultBlockState()
+                            : ModBlocks.CRYSTAL_BLOCK.get().defaultBlockState(), 3);
+        }
+        BlockPos support = helper.absolutePos(new BlockPos(0, 2, 1));
+        BlockPos holderPos = support.below();
+        BlockPlaceContext context = new BlockPlaceContext(level, null, InteractionHand.MAIN_HAND,
+                new ItemStack(ModItems.BOOK_RECEPTACLE.get()),
+                new BlockHitResult(Vec3.atCenterOf(support).add(0, -0.5, 0),
+                        Direction.DOWN, support, false));
+        var placed = ModBlocks.BOOK_RECEPTACLE.get().getStateForPlacement(context);
+        helper.assertTrue(placed != null && placed.getValue(BookReceptacleBlock.FACING) == Direction.DOWN,
+                "Clicking the underside of a Crystal Block must place a downward-facing receptacle");
+        level.setBlock(holderPos, placed, 3);
+        ((BookReceptacleBlockEntity) level.getBlockEntity(holderPos))
+                .setBook(new ItemStack(ModItems.LINKING_BOOK.get()));
+        helper.assertTrue(CrystalPortalNetwork.activate(level, holderPos, planLoaded(level, holderPos)),
+                "A ceiling-mounted receptacle must activate its horizontal crystal frame");
+        helper.assertValueEqual(level.getBlockState(helper.absolutePos(new BlockPos(1, 2, 1)))
+                .getValue(CrystalPortalBlock.AXIS), Direction.Axis.Y,
+                "The underside-mounted portal surface remains horizontal");
         helper.succeed();
     }
 
diff --git a/src/main/resources/assets/rivencraft/blockstates/book_receptacle.json b/src/main/resources/assets/rivencraft/blockstates/book_receptacle.json
index fc561ce..d21bddf 100644
--- a/src/main/resources/assets/rivencraft/blockstates/book_receptacle.json
+++ b/src/main/resources/assets/rivencraft/blockstates/book_receptacle.json
@@ -1 +1 @@
-{"variants":{"facing=north":{"model":"rivencraft:block/book_receptacle","y":180},"facing=east":{"model":"rivencraft:block/book_receptacle","y":270},"facing=south":{"model":"rivencraft:block/book_receptacle"},"facing=west":{"model":"rivencraft:block/book_receptacle","y":90},"facing=up":{"model":"rivencraft:block/book_receptacle","x":270},"facing=down":{"model":"rivencraft:block/book_receptacle","x":90}}}
+{"variants":{"facing=north":{"model":"rivencraft:block/book_receptacle","y":180},"facing=east":{"model":"rivencraft:block/book_receptacle","y":270},"facing=south":{"model":"rivencraft:block/book_receptacle"},"facing=west":{"model":"rivencraft:block/book_receptacle","y":90},"facing=up":{"model":"rivencraft:block/book_receptacle","x":90},"facing=down":{"model":"rivencraft:block/book_receptacle","x":270,"y":180}}}