Crossing the Centre: How to Cut Across the Body

Preventing Over-Rotation, Blade Drift, and Instability During Turns

In Iaijutsu, few moments feel as vulnerable as the instant your sword crosses your centreline. For a brief heartbeat, the blade is no longer aligned with your power, your posture, or your defensive structure — unless you know how to control it.

Crossing the centre isn’t just a mechanical detail. It’s a test of balance, body control, edge awareness, and intent. When done correctly, it becomes one of the strongest and safest transitions in your movement. When done poorly, it creates openings, unstable cuts, and unnecessary tension.

This blog breaks down how to move the sword across your centre with precision and confidence.

1. What “Crossing the Centre” Really Means

Your seichusen (centreline) is the vertical line running through:

the crown of the head,
spine,
pelvis,
and down between your feet.

When a technique requires the blade to pass from one side to the other — such as during:

furikaburi turns,
diagonal angle changes,
drawing to the opposite side,
or resetting the sword in kata —

you must guide the sword past this centreline without collapsing your structure.

Crossing the centre is not the problem.
Losing alignment while crossing is the problem.

2. The Three Most Common Errors (and Why They Happen)

1. Over-Rotation of the Hips

Many students swing the hips to “help” the sword turn, causing:

loss of balance,
drifting posture,
and breaking the connection between lower and upper body.

2. Blade Drift

The kissaki floats outward, usually due to:

excess shoulder tension,
poor tenouchi,
or trying to muscle the sword instead of guiding it.

3. Elbows Collapsing

Pulling the elbows inward during the transition constricts the movement and kills hasuji control.

These errors come from fear of being “open,” which leads students to rush the movement. Ironically, rushing makes the opening worse.

3. Principle 1: Keep the Blade Close, Not Wide

A safe, controlled centre crossing keeps the sword inside your personal frame, not flaring out to the side.

Imagine a narrow corridor around your torso.
The sword should travel through this corridor with:

the tsuka close to your body,
elbows pointed slightly down,
and the kissaki guided by the forearms.

A wide blade arc exposes your centre and slows recovery.

4. Principle 2: Let the Hips Lead, Not Twist

The body should turn as a unit, not as separate parts.

Correct method:

Hips rotate gently
Shoulders follow naturally
Hands adjust last

Incorrect method:

Shoulders yank first
Hips lag
Sword whips across out of sync

This creates over-rotation and wobble.

If the hips move first, the sword will follow smoothly.
If the sword moves first, the body will chase it — badly.

5. Principle 3: Maintain Vertical Posture Throughout the Transition

As the sword crosses the centre, the spine needs to stay:

tall,
balanced,
and stable.

Avoid the “dip” — where students lean left or right to “make room” for the blade.

A stable upright posture ensures:

clean power transfer,
predictable angles,
and readiness to cut immediately after turning.

6. Principle 4: Tenouchi Controls the Kissaki

During centre crossing, the hands do minimal work, but crucial work.

Key details:

The left hand guides the sword’s path
The right hand adjusts kissaki direction with micro-shibori
Grip should be relaxed but precise

Tenouchi is the difference between a blade that drifts outward
and one that tracks true.

7. Principle 5: Move at Half Speed Until It’s Clean

As with all Iaijutsu fundamentals, slow practice reveals the truth.

Train the centre-crossing transition at:

half speed for movement,
full awareness for posture,
minimal power,
maximal control.

Once the line is stable, speed naturally increases.

8. Solo Drills to Improve Centre Crossing

Drill 1: The “Railroad Track” Transition

Stand feet hip-width
Imagine two rails your sword must travel between
Move the sword from right to left hip without leaving the rails

Teaches path consistency.

Drill 2: Hip-First Turns

Hands on hips
Practise turning 30°, 45°, and 60° without shoulder lag
Add the sword later

Builds unified body movement.

Drill 3: Kissaki Tracking

Use a mirror
Watch how the kissaki moves across the centre
Aim for a straight, controlled arc

Prevents drift.

9. In Waza: Why This Matters

Centre crossing appears in nearly every kata — often at moments of highest vulnerability.

Examples:

Furikaburi into kirioroshi
Changing angle before nukitsuke
Turning toward a new attacker
Resetting the blade during noto preparation

Smooth, disciplined centre crossing:

keeps the cut stable,
preserves maai,
maintains constant readiness,
and eliminates unnecessary openings.

It is invisible skill — the kind that separates clean Iaijutsu from messy.

10. Final Thought: Crossing the Centre Is a Test of Your “Middle”

This transition exposes the truth of your:

posture,
balance,
timing,
grip,
and awareness.

When you can cross your centre smoothly, quietly, and without tension, your Iaijutsu becomes more connected — not driven by arms, but by unified body movement.

Master this, and every turn, cut, and reset in your waza becomes more stable and more alive.