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Choosing when to leave,
from the day's twelve blocks

Timing · August 2026 · 6 min read

Can you choose a departure time from your chart too?

On most trips the date isn't yours to pick. The leave is fixed and the tickets are bought. But the hour is choosable far more often than you'd think — morning flight or afternoon flight, which train, what time you walk out the door. There's usually a choice in there somewhere.

What are the twelve sijin?

Sijin (시진) are the twelve two-hour blocks the 24-hour day divides into. Each of the twelve earthly branches takes one block, so just as a date carries a branch, so does an hour.

There's one Korean particularity here. Korean standard time is set to 135° east. Seoul sits at about 127° east, which puts the clock roughly 30 minutes ahead of where the sun actually is. So the widely used approach is to push the sijin boundaries back by half an hour.

How do I find my own hour?

Same principle as choosing a date. The good hour to set out is the sijin whose branch pairs with your day branch (or your animal).

Take the six yukhap pairs and map them straight onto the clock.

You'll spot the problem immediately. The Rat's pairing hour is two in the morning. Not many trips leave then. So here's how it works in practice.

• Within the options you actually have, pick the nearer one. Just whichever of the morning or afternoon flight sits closer to your hour.
• If your pairing hour lands in the small hours, simply avoid the clashing sijin. A Rat wouldn't go out of their way to depart during O (11:30–13:30).
• Read the sijin against the moment you leave — not your arrival at the airport or your boarding time, but the moment you walk out the door.

What time should I head for the airport?

This is the part that comes up most on an actual trip. It's also the part where reality outranks the chart.

Before the sijin comes the slack. Leaving on a good hour and then missing the flight helps nobody.

Think of it as laying the sijin on top, in this order.

• Work out when you need to arriveThree hours ahead for international, an hour and a half for domestic, as a rule of thumb.
• Count back to when you leave the houseThat's the reality part done.
• If two options sit near that time, let the sijin chooseBetween 7:20 and 7:45, take 7:45 — it falls inside Jin (07:30–).

Which clock do I use when there's a time difference?

Good question, and the answer is the clock where you started.

Departing is something that happens at the place you depart from, so read the sijin in that region's time. Once you've landed, read that day's sijin in local time from then on.

What if I can't choose the time either?

Then choose what you can. There are more layers you can adjust on a trip than most people assume.

That last row is the heart of it. Even on a trip where the date, the direction and the hour are all out of your hands, the order of things inside the itinerary almost always isn't. Putting the most important plan on the best of three days is already half of what choosing a date is for.

5htrip sends you the day's sijin rhythm each morning, marking one window to lean into and one to leave open, so even mid-trip it's easy to decide where to load up the day. It's all almanac math, so it's free every day.