diff --git a/CHANGES b/CHANGES
index 50e7ce57a..c3d039841 100644
--- a/CHANGES
+++ b/CHANGES
@@ -19,9 +19,15 @@ $ pip install --user --upgrade --pre libtmux
 
 #### Improved new sessions (#532)
 
-- `Session.new_window()` to {meth}`Session.new_window()`
+- `Session.new_window()`:
 
   - Learned `direction`, via {class}`~libtmux.constants.WindowDirection`).
+  - [PEP 3102] keyword-only arguments after window name (#534).
+
+- Added {meth}`Window.new_window()` shorthand to create window based on that
+  window's position.
+
+[PEP 3102]: https://www.python.org/dev/peps/pep-3102/
 
 #### Improved window splitting (#532)
 
diff --git a/src/libtmux/pane.py b/src/libtmux/pane.py
index 2ef250c5c..5826bdbc7 100644
--- a/src/libtmux/pane.py
+++ b/src/libtmux/pane.py
@@ -149,6 +149,7 @@ def cmd(self, cmd: str, *args: t.Any) -> tmux_cmd:
 
     def resize(
         self,
+        /,
         # Adjustments
         adjustment_direction: t.Optional[ResizeAdjustmentDirection] = None,
         adjustment: t.Optional[int] = None,
@@ -489,6 +490,8 @@ def select_pane(self) -> "Pane":
 
     def split(
         self,
+        /,
+        target: t.Optional[t.Union[int, str]] = None,
         start_directory: t.Optional[str] = None,
         attach: bool = False,
         direction: t.Optional[PaneDirection] = None,
@@ -502,6 +505,8 @@ def split(
 
         Parameters
         ----------
+        target : optional
+            Optional, custom *target-pane*, used by :meth:`Window.split`.
         attach : bool, optional
             make new window the current window after creating it, default
             True.
@@ -615,6 +620,9 @@ def split(
         if not attach:
             tmux_args += ("-d",)
 
+        if target is not None:
+            tmux_args += (f"-t{target}",)
+
         if environment:
             if has_gte_version("3.0"):
                 for k, v in environment.items():
@@ -805,6 +813,7 @@ def at_right(self) -> bool:
     #
     def split_window(
         self,
+        target: t.Optional[t.Union[int, str]] = None,
         attach: bool = False,
         start_directory: t.Optional[str] = None,
         vertical: bool = True,
@@ -842,6 +851,7 @@ def split_window(
         if size is None and percent is not None:
             size = f'{str(percent).rstrip("%")}%'
         return self.split(
+            target=target,
             attach=attach,
             start_directory=start_directory,
             direction=PaneDirection.Below if vertical else PaneDirection.Right,
diff --git a/src/libtmux/session.py b/src/libtmux/session.py
index a85ac8341..01406404c 100644
--- a/src/libtmux/session.py
+++ b/src/libtmux/session.py
@@ -537,6 +537,7 @@ def rename_session(self, new_name: str) -> "Session":
     def new_window(
         self,
         window_name: t.Optional[str] = None,
+        *,
         start_directory: None = None,
         attach: bool = False,
         window_index: str = "",
@@ -635,6 +636,10 @@ def new_window(
         if window_name is not None and isinstance(window_name, str):
             window_args += ("-n", window_name)
 
+        if window_index is not None:
+            # empty string for window_index will use the first one available
+            window_args += (f"-t{self.session_id}:{window_index}",)
+
         if environment:
             if has_gte_version("3.0"):
                 for k, v in environment.items():
diff --git a/src/libtmux/window.py b/src/libtmux/window.py
index 5d6047660..9795f47d1 100644
--- a/src/libtmux/window.py
+++ b/src/libtmux/window.py
@@ -199,6 +199,7 @@ def select_pane(self, target_pane: t.Union[str, int]) -> t.Optional["Pane"]:
 
     def split(
         self,
+        /,
         target: t.Optional[t.Union[int, str]] = None,
         start_directory: t.Optional[str] = None,
         attach: bool = False,
@@ -238,6 +239,7 @@ def split(
         """
         active_pane = self.active_pane or self.panes[0]
         return active_pane.split(
+            target=target,
             start_directory=start_directory,
             attach=attach,
             direction=direction,
@@ -250,6 +252,7 @@ def split(
 
     def resize(
         self,
+        /,
         # Adjustments
         adjustment_direction: t.Optional[ResizeAdjustmentDirection] = None,
         adjustment: t.Optional[int] = None,
@@ -621,6 +624,7 @@ def move_window(
     def new_window(
         self,
         window_name: t.Optional[str] = None,
+        *,
         start_directory: None = None,
         attach: bool = False,
         window_index: str = "",