diff --git a/README.md b/README.md
index 00a6724..d1bc529 100644
--- a/README.md
+++ b/README.md
@@ -98,7 +98,7 @@ batch_multi_assign :: chunk | query, fragment[], component[]? -> integer, boolea
 batch_multi_insert :: chunk | query, fragment[], component[]? -> integer, boolean
 batch_multi_remove :: chunk | query, fragment[] -> integer, boolean
 
-chunk :: fragment... -> chunk?, entity[]?, integer?
+chunk :: fragment, fragment... -> chunk, entity[], integer
 
 entities :: chunk -> entity[], integer
 fragments :: chunk -> fragment[], integer
diff --git a/ROADMAP.md b/ROADMAP.md
index 0315482..5877029 100644
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -3,11 +3,11 @@
 ## Backlog
 
 - should set/assign/insert return a constructed component?
-- chunk(...) check for 0 fragments
 
 ## After first release
 
 - add system groups
+- observers and events
 - add INDEX fragment trait
 - add REQUIRES fragment trait
 - use compact prefix-tree for chunks
diff --git a/develop/unbench.lua b/develop/unbench.lua
index 0c78fe0..8266781 100644
--- a/develop/unbench.lua
+++ b/develop/unbench.lua
@@ -619,7 +619,7 @@ basics.describe_bench(string.format('create and destroy %d entities / spawn_at',
         local fragments = {}
         local components = {}
 
-        local chunk = evo.chunk()
+        local chunk = nil
 
         for i = 1, N do
             entities[i] = spawn_at(chunk, fragments, components)
diff --git a/develop/untests.lua b/develop/untests.lua
index b489f05..5fbff34 100644
--- a/develop/untests.lua
+++ b/develop/untests.lua
@@ -647,11 +647,6 @@ do
     assert(evo.insert(e2b, f1, 44))
     assert(evo.insert(e2b, f2, 45))
 
-    do
-        local chunk, entities = evo.chunk()
-        assert(not chunk and not entities)
-    end
-
     do
         local chunk, entities = evo.chunk(f1)
         assert(entities and entities[1] == e1)
diff --git a/evolved.lua b/evolved.lua
index 198e351..206d453 100644
--- a/evolved.lua
+++ b/evolved.lua
@@ -674,6 +674,7 @@ local __evolved_batch_multi_insert
 local __evolved_batch_multi_remove
 
 local __evolved_chunk
+
 local __evolved_entities
 local __evolved_fragments
 local __evolved_components
@@ -1175,25 +1176,19 @@ end
 ---
 ---
 
----@param ... evolved.fragment fragments
----@return evolved.chunk?
+---@param head_fragment evolved.fragment
+---@param ... evolved.fragment tail_fragments
+---@return evolved.chunk
 ---@nodiscard
-local function __chunk_fragments(...)
-    local fragment_count = __lua_select('#', ...)
+local function __chunk_fragments(head_fragment, ...)
+    local chunk = __root_chunks[head_fragment]
+        or __chunk_with_fragment(nil, head_fragment)
 
-    if fragment_count == 0 then
-        return
-    end
-
-    local root_fragment = ...
-    local chunk = __root_chunks[root_fragment]
-        or __chunk_with_fragment(nil, root_fragment)
-
-    for i = 2, fragment_count do
+    for i = 1, __lua_select('#', ...) do
         ---@type evolved.fragment
-        local child_fragment = __lua_select(i, ...)
-        chunk = chunk.__with_fragment_edges[child_fragment]
-            or __chunk_with_fragment(chunk, child_fragment)
+        local tail_fragment = __lua_select(i, ...)
+        chunk = chunk.__with_fragment_edges[tail_fragment]
+            or __chunk_with_fragment(chunk, tail_fragment)
     end
 
     return chunk
@@ -5037,8 +5032,7 @@ __evolved_is_empty = function(chunk_or_entity)
         local entity = chunk_or_entity --[[@as evolved.entity]]
 
         local entity_index = entity % 0x100000
-        return __freelist_ids[entity_index] ~= entity
-            or not __entity_chunks[entity_index]
+        return __freelist_ids[entity_index] ~= entity or not __entity_chunks[entity_index]
     end
 end
 
@@ -7088,22 +7082,18 @@ end
 ---
 ---
 
----@param ... evolved.fragment fragments
----@return evolved.chunk? chunk
----@return evolved.entity[]? entity_list
----@return integer? entity_count
+---@param head_fragment evolved.fragment
+---@param ... evolved.fragment tail_fragments
+---@return evolved.chunk chunk
+---@return evolved.entity[] entity_list
+---@return integer entity_count
 ---@nodiscard
-__evolved_chunk = function(...)
+__evolved_chunk = function(head_fragment, ...)
     if __debug_mode then
-        __validate_fragments(...)
-    end
-
-    local chunk = __chunk_fragments(...)
-
-    if not chunk then
-        return
+        __validate_fragments(head_fragment, ...)
     end
 
+    local chunk = __chunk_fragments(head_fragment, ...)
     return chunk, chunk.__entity_list, chunk.__entity_count
 end