Everything You Need to Know Before You Buy — The Ultimate 2026 Ticket Guide

So you’ve booked your flights, chosen your hotel in Wulingyuan, and packed your hiking shoes. You’re ready to walk among the floating sandstone pillars of Zhangjiajie National Forest Park (张家界国家森林公园). But there’s one critical step standing between you and those iconic Avatar mountains: understanding the ticket system. 🌿🏔️

Here’s the truth: Zhangjiajie’s ticketing system is not like buying a simple entry pass at a theme park. It involves real-name registration, biometric fingerprint scanning, time-divided entry slots, multiple internal transport options, and a 4-day validity window that confuses even experienced travelers. Add in the language barrier, and you’ve got a recipe for expensive mistakes, wasted hours, and unnecessary stress. 😰

But don’t worry! This guide breaks down every single detail about the Zhangjiajie National Forest Park ticket system. From pricing and booking methods to what’s included, what’s excluded, and how to maximize your 4-day pass for the ultimate hiking experience—we’ve got you covered. Let’s decode the system together! 🎟️✨

🌍 1. The Big Picture: What is the Wulingyuan Scenic Area Ticket?

Before we talk about prices and booking, let’s clarify what you’re actually purchasing.

The Name Confusion 🤔

You’ll see multiple names used interchangeably:

“Zhangjiajie National Forest Park Ticket”
“Wulingyuan Scenic Area Pass”
“Zhangjiajie 4-Day Ticket”
“Wulingyuan Entrance Fee”

They all refer to the SAME ticket. ✅

The Wulingyuan Scenic Area is the UNESCO World Heritage zone that encompasses multiple parks, including:

🌲 Zhangjiajie National Forest Park (the core area with Avatar mountains)
⛰️ Tianzi Mountain Nature Reserve
🏔️ Suoxiyu Nature Reserve
🌊 Yangjiajie Scenic Area

Your single 4-day ticket grants you access to ALL of these areas. You don’t need separate tickets for Yuanjiajie, Tianzi Mountain, Golden Whip Stream, or Yangjiajie—they’re all covered under one pass! 🎉

The 4-Day Validity Window ⏰

The ticket is valid for 4 consecutive calendar days from the date of first entry. This means:

Day 1: First entry (fingerprint scanned)
Day 2: Re-entry allowed
Day 3: Re-entry allowed
Day 4: Final day of validity
Day 5: Ticket expires ❌

You can enter and exit the park multiple times per day during this 4-day window. This is crucial for planning multi-day hiking itineraries! 🚶‍♂️🚶‍♀️

💰 2. 2026 Ticket Prices: What You’ll Actually Pay

Standard Adult Ticket 🎫

Category	Price (RMB)	Price (USD Approx.)
Peak Season (March 1 – November 30)	227 RMB	~$31 USD
Off Season (December 1 – February 28)	147 RMB	~$20 USD

Note: Prices are set by the Hunan Provincial Development and Reform Commission and may be adjusted annually. The figures above reflect the most recent standard rates. Always verify current pricing before your trip.

What Does the Price Cover?

The 227 RMB (peak) or 147 RMB (off-season) ticket includes:

✅ 4-day unlimited entry to ALL areas within Wulingyuan Scenic Area
✅ Unlimited use of the Eco-Shuttle Bus system inside the park (the green buses that transport you between trailheads, viewpoints, and transport hubs)
✅ Access to all hiking trails, viewing platforms, and scenic areas
✅ Basic travel insurance (a small portion of the ticket price goes toward a mandatory insurance fee)

Price Breakdown (Where Your Money Goes) 🔍

Scenic Area Entry Fee: ~180 RMB (peak) / ~100 RMB (off-season)
Eco-Bus Fee: ~33 RMB (peak) / ~33 RMB (off-season)
Insurance Fee: ~3 RMB
Resource Protection Fee: ~11 RMB

✅ 3. What’s INCLUDED in the 4-Day Pass

Let’s be crystal clear about what your ticket gets you:

🌲 All Five Core Scenic Areas:

Yuanjiajie (袁家界): The famous Avatar Hallelujah Mountain, First Bridge Under Heaven, Enchanting Stage, and Back Garden.
Tianzi Mountain (天子山): Imperial Writing Brush Peak, Fairy Scattering Flowers, Helong Park, and the Sea of Clouds viewing platforms.
Golden Whip Stream (金鞭溪): The 7.5 km valley-floor hiking trail with crystal-clear streams and macaque monkeys.
Yangjiajie (杨家界): The Great Wall of Natural Stone, Wulong Cave, and the rugged cliff trails.
Yellow Stone Village / Huangshizhai (黄石寨): The iconic flat-topped mountain with 360-degree panoramic views.

🚌 Unlimited Eco-Shuttle Bus Rides:

The park’s internal transportation network is free and unlimited with your ticket. These green-and-white buses run on fixed routes connecting:

All five entry gates
The base stations of cable cars and elevators
Major trailheads and viewpoints
Service areas and rest stops

You can hop on and off as many times as you like, in any direction, on any route. No extra charge! 🚌💨

🚶 All Hiking Trails and Walking Paths:

Every paved path, wooden boardwalk, stone staircase, and cliff-side walkway within the park boundaries is included. No hidden “trail fees” or “viewpoint surcharges.” 🥾

📸 All Viewing Platforms:

Every photographic viewpoint, glass observation deck (within the main park areas), and scenic overlook is accessible with your ticket.

❌ 4. What’s NOT Included (Extra Costs to Budget For)

This is where many tourists get caught off guard. Your 4-day pass does NOT cover the following:

🚡 Vertical Transportation (Cable Cars & Elevators)

Transport	One-Way Price	Round-Trip Price	Location
Bailong Elevator (百龙天梯)	~72 RMB	~144 RMB	Yuanjiajie cliff face
Tianzi Mountain Cable Car (天子山索道)	~67 RMB	~134 RMB	Tianzi Mountain
Yellow Stone Village Cable Car (黄石寨索道)	~65 RMB	~130 RMB	Yellow Stone Village
Yangjiajie Cable Car (杨家界索道)	~67 RMB	~134 RMB	Yangjiajie
Ten-Mile Gallery Mini-Train (十里画廊小火车)	~38 RMB	~76 RMB	Valley floor near Tianzi

💡 Budget Tip: If you plan to use the Bailong Elevator AND the Tianzi Cable Car (the most common combo), budget an extra ~140-150 RMB ($20-$21 USD) per person. For a 2-day visit using multiple transports, set aside 200-300 RMB ($28-$42 USD) total.

🌉 Separate Attractions Outside the Park

These are NOT included in your Wulingyuan pass and require separate tickets:

Zhangjiajie Grand Canyon & Glass Bridge: ~259 RMB (separate park, 30 min drive away)
Tianmen Mountain: ~278 RMB (separate park in the city center)
Baofeng Lake: ~96 RMB (separate scenic spot)
Yellow Dragon Cave (Huanglongdong): ~100 RMB (separate cave system)

🍜 Food, Drinks, and Souvenirs Inside the Park

Meals at mountain-top restaurants: 40-80 RMB per person
Snacks (corn, sausages, instant noodles): 10-25 RMB
Bottled water: 5-10 RMB (cheaper at the base, expensive at the summit!)

🚕 External Transportation

Taxi/Didi from your hotel to the park gate
Private guides or porters (if hired)
Luggage storage at the gate (usually free, but verify)

🛂 5. The Real-Name Registration System Explained

What is Real-Name Registration? 📝

China’s major tourist attractions operate on a Real-Name Ticketing System (实名制购票). This means:

Every ticket is linked to a specific person’s identity document.
For Chinese citizens: National ID card (身份证).
For foreign tourists: Passport (护照).
You cannot buy a ticket anonymously or transfer it to another person.

Why Does This Matter for You? 🤔

You MUST bring your physical passport to the park entrance. A photo on your phone is NOT sufficient.
Your passport number is entered into the system when you purchase the ticket.
At the gate, staff will verify that the passport matches the booking.
One passport = One ticket per day. You cannot use the same passport to buy multiple tickets for the same date.

⚠️ Critical Warning

NEVER buy tickets from street touts, unlicensed tour operators, or “discount” sellers outside the park gates. These tickets may be:

Registered to someone else’s ID (you’ll be denied entry)
Fake or expired
Linked to a fraudulent booking

Only purchase through official channels (listed in Section 8 below). 🚫🎫

🔐 6. The Biometric Fingerprint System: How It Works

The Fingerprint Process 👆

When you enter the park for the first time on Day 1:

You approach the ticket gate with your passport.
The staff scans your passport barcode/QR code.
You place your index finger (or thumb) on a biometric scanner.
The system captures your fingerprint and links it to your 4-day pass.
The turnstile opens. You’re in! 🎉

On Days 2, 3, and 4:

You simply walk to the gate and place your finger on the scanner.
The system recognizes your fingerprint and verifies your ticket is still valid.
No need to show your passport again (though carrying it is always wise).
The turnstile opens. Walk in! ✅

What If the Fingerprint Doesn’t Scan? 🤷

Sometimes cold weather, wet fingers, or worn fingerprints (from manual labor) can cause scanning issues.
If this happens, go to the Manual Service Window next to the gates.
Show your passport, and staff will manually verify your ticket and let you through.
Don’t panic—this is a common occurrence and is easily resolved! 😊

⏰ 7. Time-Divided Entry: Choosing Your Slot

What is Time-Divided Entry? 🕐

To manage crowd flow (especially during peak season), Zhangjiajie National Forest Park has implemented a Time-Divided Entry System (分时段预约入园). This means:

When you book your ticket, you may be asked to select an entry time slot.
Common slots: Morning (7:00 AM – 12:00 PM) and Afternoon (12:00 PM – 5:00 PM).
You must enter the park within your chosen time slot on Day 1.

Does This Affect Days 2, 3, and 4? 🔄

Day 1: You must enter during your booked slot.
Days 2-4: You can typically enter at any time during operating hours (no strict slot enforcement for re-entry). However, during extreme peak periods (Golden Week), re-entry may also require slot booking.

Pro Tips for Time Slots 💡

Always book the MORNING slot (7:00 AM – 12:00 PM). This gets you into the park early, before the massive tour bus groups arrive at 9:00-10:00 AM.
If you’re staying in Wulingyuan (a 5-15 minute walk to the gate), aim to arrive at 7:00-7:30 AM for the peaceful, misty morning experience. 🌅
Afternoon slots are fine if you’re arriving late in Zhangjiajie or spending the morning exploring Wulingyuan town.

🛒 8. How to Buy Tickets: Online vs. In-Person

Method 1: Buy at the Park Gate (In-Person) 🏢

Where: The ticket windows at any of the 5 entry gates (Wulingyuan Gate, Zimugang Gate, Tianzi Mountain Gate, Yangjiajie Gate, Zhongzimen Gate).

Process:

Go to the “Foreigner / Passport” window (usually marked with a sign showing a passport icon 🛂).
Hand over your physical passport.
State how many tickets you need and for which date.
Pay via WeChat Pay, Alipay, or cash (though cash is increasingly rare—have mobile payment ready!).
Receive your ticket receipt (keep it safe, though the fingerprint is your real “ticket”).

Pros:

Simple and straightforward.
No need to navigate Chinese apps.
Staff at the foreigner window are usually experienced with international visitors.

Cons:

Long queues during peak season (July-August, October holidays).
Risk of tickets being sold out for the day during extreme peak periods.
Language barrier possible if the foreigner window is closed.

Best For: Travelers arriving without advance plans, off-season visitors, or those uncomfortable with Chinese booking apps.

Method 2: Book Online in Advance 📱

Option A: Through Your Hotel or Travel Agency

Most hotels in Wulingyuan offer a ticket booking service for guests.
Email or message your hotel 2-3 days before arrival with your passport details (full name, passport number, nationality, desired entry date).
They’ll book the ticket and confirm. You pay at check-in or via mobile payment.
This is the EASIEST method for international tourists. ✅

Option B: Official WeChat Mini-Program (For Tech-Savvy Travelers)

Search for the official Wulingyuan Scenic Area booking mini-program on WeChat.
Select “Foreign Passport” as your ID type.
Enter your details and select your time slot.
Pay via WeChat Pay.
Note: The interface may be partially in Chinese. Have a translation app ready.

Option C: Through Trip.com or Similar Platforms

Some international travel platforms offer Zhangjiajie ticket booking with English interfaces.
Look for “Zhangjiajie National Forest Park Ticket” or “Wulingyuan Scenic Area Pass.”
You’ll need to provide passport details at booking.

Option D: Through a Licensed Tour Guide

If you’ve hired a local guide for your Zhangjiajie trip, they can handle all ticket bookings for you.
This is the most hassle-free option but adds a service fee.

📋 Booking Checklist (Have These Ready!)

Before booking, prepare:

✅ Full name exactly as it appears on your passport
✅ Passport number
✅ Nationality
✅ Desired entry date (Day 1)
✅ Preferred time slot (Morning/Afternoon)
✅ Number of travelers
✅ Payment method (Alipay/WeChat Pay linked to foreign card)

🏷️ 9. Discount Tickets: Who Qualifies?

Zhangjiajie National Forest Park offers discounted or free entry for certain categories of visitors:

🎓 Students

Discount: ~50% off the standard ticket price.
Requirement: Valid student ID card (international student cards are sometimes accepted, but policies vary). Must be a full-time student under 24.
Note: Bring your physical student ID. Digital copies may not be accepted.

👴 Seniors (Age 60+)

Age 60-69: ~50% discount.
Age 70+: FREE entry (must show valid ID/passport proving age).
Note: For foreign tourists, your passport serves as age verification.

👶 Children

Under 1.2 meters tall (approx. 3’11”): FREE entry.
1.2m – 1.4m tall: ~50% discount.
Over 1.4m: Full adult price.
Note: Height is measured at the gate. Bring kids to the measurement station if unsure.

🎖️ Military Personnel / Disabled Persons

Active military: Free or heavily discounted.
Disabled persons (with valid disability certificate): Free or heavily discounted.
Note: Foreign military IDs or disability certificates may require verification. Check with the ticket window.

⚠️ Important Note on Discounts

Discount policies can change annually. Always verify current discount eligibility at the official ticket window or through your hotel before assuming you qualify. Bring ALL relevant physical documents (student IDs, passports, disability certificates). 📄

🔄 10. Refunds, Changes, and Cancellation Policies

Can I Get a Refund? 💸

Before first entry (ticket unused): Generally, yes. If you booked online and haven’t entered the park, you can usually request a refund through the booking platform. Processing takes 3-7 business days.
After first entry (fingerprint scanned): NO REFUND. Once your fingerprint is registered and you enter the park on Day 1, the ticket is considered “used” regardless of how many of the 4 days you actually visit.
Weather cancellations: If the park officially closes due to extreme weather (typhoons, landslides), refunds or date changes may be offered. This is rare.

Can I Change My Entry Date? 📅

Before first entry: Usually possible through the booking platform or by contacting the ticket office. Subject to availability.
After first entry: No changes possible. Your 4-day window starts from Day 1 entry.

What If I Lose My Passport During the 4 Days? 😱

Your ticket is linked to your fingerprint, not just your passport.
On Days 2-4, you can usually enter using just your fingerprint at the scanner.
However, if the fingerprint fails and you need manual verification, you’ll need your passport.
Always carry a photocopy/photo of your passport as backup. If you lose the original, report it to your embassy immediately.

🏆 11. How to Maximize Your 4-Day Pass

You’ve paid for 4 days—use them wisely! Here’s how to get the absolute most value from your ticket:

📅 Recommended 3-Day Itinerary (Most Common)

Day 1: The Iconic Peaks 🏔️

Enter via Wulingyuan Gate (East Gate) at 7:00 AM.
Take the Eco-Bus to Bailong Elevator. Ride up (72 RMB extra).
Explore Yuanjiajie (Avatar Hallelujah Mountain, First Bridge Under Heaven).
Take the Eco-Bus to Tianzi Mountain. Explore the cliff-edge viewpoints.
Take the Tianzi Cable Car down (67 RMB extra).
Eco-Bus back to East Gate. Exit by 4:00 PM.

Day 2: The Valley Floor 🌊

Enter via Zimugang Gate (South Gate) or East Gate.
Hike the full Golden Whip Stream trail (7.5 km, ~2.5 hours).
Continue to Water Winding Four Gates (Shuirao Men).
Afternoon: Take the cable car up to Yellow Stone Village (65 RMB extra). Walk the 2-hour summit loop.
Cable car down. Exit.

Day 3: The Hidden Gem 🌲

Enter via Yangjiajie Gate (West Gate) or East Gate.
Explore Yangjiajie: Great Wall of Natural Stone, Wulong Cave.
Hike the less-crowded trails. Enjoy the solitude!
Optional: Revisit your favorite viewpoint from Day 1 or 2 for different lighting.

Day 4: Flexible / Backup Day 🔄

Use for: Revisiting a spot you loved, catching a sunrise, exploring an area you missed, or simply resting your legs!
If the weather was bad on Day 1 or 2, use Day 4 to redo the hike in better conditions.

💡 Pro Tips for Maximizing Value

Enter EARLY. The park opens around 7:00 AM (varies slightly by season). Being at the gate by 7:00 means you’ll beat the tour groups and get the best morning light for photos. 🌅
Use the Eco-Buses strategically. They’re free and unlimited. Don’t waste energy walking 3 km on a flat road when a bus can take you there in 5 minutes.
Combine high and low. Do one high-altitude day (Yuanjiajie/Tianzi) and one valley-floor day (Golden Whip Stream) to rest different muscle groups.
Check the weather daily. If Day 1 is foggy, swap your itinerary. Do the valley hike on the bad day and save the peaks for the clear day. Your 4-day pass gives you this flexibility! ☁️➡️☀️

❌ 12. Common Ticket Mistakes Tourists Make

Mistake #1: Buying from Street Touts 🚫

The Problem: Unofficial sellers outside the gate offer “discounted” tickets. They’re either fake, registered to someone else, or expired.
The Fix: ONLY buy at official ticket windows or through your hotel/verified platforms.

Mistake #2: Forgetting Your Passport 🛂

The Problem: You arrive at the gate without your physical passport. You cannot enter.
The Fix: Keep your passport in a secure, easily accessible pocket. Set a phone reminder the night before: “BRING PASSPORT TO PARK!” 📱

Mistake #3: Not Understanding the 4-Day Window 📅

The Problem: Tourists think they can “save” days and use them non-consecutively (e.g., Day 1, then skip 3 days, then Day 2).
The Fix: The 4 days are CONSECUTIVE calendar days. Day 1 is your first entry. Day 4 is the last day you can enter. Plan accordingly!

Mistake #4: Assuming Cable Cars are Included 🚡

The Problem: Tourists budget only for the 227 RMB ticket, then are surprised by 72 RMB for the Bailong Elevator, 67 RMB for the cable car, etc.
The Fix: Budget an extra 200-300 RMB per person for internal transport if you plan to use elevators and cable cars.

Mistake #5: Arriving at the Wrong Gate 🚪

The Problem: You booked entry for Wulingyuan Gate (East) but show up at Zimugang Gate (South).
The Fix: Your ticket is valid at ALL gates. You can enter from any gate on any day. But plan your route based on which gate is closest to your planned hiking trail for that day.

Mistake #6: Trying to Enter After the 4-Day Window ⏰

The Problem: You enter on Monday (Day 1). You think Thursday is still valid. But actually, Monday=Day 1, Tuesday=Day 2, Wednesday=Day 3, Thursday=Day 4. Friday is expired.
The Fix: Count carefully! If you enter on Monday, your last valid day is Thursday.

Mistake #7: Not Booking a Time Slot During Peak Season 🕐

The Problem: During October Golden Week or summer peak, you show up without a pre-booked slot and are turned away or face a 2-hour queue.
The Fix: During peak months, ALWAYS book your time slot in advance (via hotel or online).

❓ 13. FAQ: Your Top Ticket Questions Answered

Q: Can I enter the park multiple times in one day? A: ✅ Yes! Your ticket allows unlimited entries and exits within the 4-day window. You can leave for lunch in Wulingyuan town and come back in the afternoon.

Q: Is the Eco-Shuttle Bus really free? A: ✅ Yes! The green shuttle buses inside the park are included in your ticket price. Hop on and off as many times as you want on any route. No extra charge. 🚌

Q: Can I use the same ticket for Tianmen Mountain or the Glass Bridge? A: ❌ No! Tianmen Mountain, Zhangjiajie Grand Canyon (Glass Bridge), Baofeng Lake, and Yellow Dragon Cave are separate attractions with their own tickets. Your Wulingyuan pass only covers the National Forest Park.

Q: What happens if it rains heavily? Can I get a refund? A: ⚠️ Generally, no. The park remains open in rain (unless there’s a safety closure). Rain and fog are actually part of the Zhangjiajie experience—the misty peaks look incredible! However, if the park officially closes due to extreme weather, refunds or date changes may be offered.

Q: Do I need to book a separate ticket for each of the 4 days? A: ❌ No! One ticket covers all 4 consecutive days. You only pay once. Your fingerprint is your “ticket” for re-entry.

Q: Can I lend my ticket to a friend for Day 3 if I’m not going? A: ❌ Absolutely not. The ticket is linked to YOUR fingerprint and YOUR passport. It is non-transferable. Your friend must buy their own ticket.

Q: Are there ATMs or ticket machines inside the park? A: 🚫 No ATMs inside. There are small shops selling snacks and drinks, but no banking services. Ensure you have enough cash/mobile payment before entering. Some spots accept WeChat/Alipay, but signal can be spotty on the mountain.

Q: Is there a locker/luggage storage at the gate? A: ✅ Yes. Most major gates (especially Wulingyuan East Gate) have luggage storage facilities. Cost: ~10-20 RMB per bag per day. Useful if you’re checking out of your hotel but want to hike before catching your train. 🧳

Q: Can I buy the ticket with a foreign credit card at the gate? A: ⚠️ Unlikely. Most ticket windows accept WeChat Pay, Alipay, or Chinese UnionPay cards. Cash (RMB) is sometimes accepted but increasingly rare. Set up Alipay/WeChat Pay with your foreign card BEFORE arriving.

Q: I’m visiting in December. Is the park open? A: ✅ Yes! The park is open year-round. December-February is “off-season” with lower ticket prices (147 RMB) and fewer crowds. However, some trails may be icy, and cable cars may have reduced hours. Dress warmly! 🧣❄️

Q: Do I need to book tickets for children? A: 👶 Children under 1.2m tall enter FREE (no ticket needed). Children between 1.2m-1.4m get a half-price ticket. Over 1.4m pays full price. Height is measured at the gate.

Q: What if I lose my ticket receipt? A: 😊 Don’t worry! The receipt is just a backup. Your actual “ticket” is your fingerprint in the system. As long as your fingerprint scans correctly, you can enter without the paper receipt.

Q: Can I upgrade my ticket to include cable cars? A: 🚫 No. Cable cars and elevators are operated by separate companies. You must purchase them separately at their respective stations. There is no “all-inclusive” upgrade at the main gate.

Q: Is there a group discount for 10+ people? A: 📞 Possibly. Group bookings (usually 10+ people) may qualify for a small discount or priority entry. Contact the park’s group booking office or arrange through a licensed travel agency.

📝 Final Checklist: Your Ticket To-Do List

Before you head to Zhangjiajie, run through this checklist:

✅ Decide your entry date (Day 1) and book 2-3 days in advance
✅ Choose your time slot (Morning recommended)
✅ Confirm your passport details are ready for booking
✅ Set up Alipay or WeChat Pay with your foreign credit card
✅ Budget extra for cable cars/elevators (200-300 RMB per person)
✅ Confirm which gate you’ll enter from (based on your hotel location)
✅ Pack your physical passport in an accessible pocket
✅ Download offline maps of the park (trail routes, gate locations)
✅ Check the weather forecast for your 4-day window
✅ Confirm your hotel can help with ticket booking (if needed)

🌟 Final Thoughts: Your Ticket is Your Golden Key

The Zhangjiajie National Forest Park ticket isn’t just an entry fee—it’s your 4-day golden key to one of the most extraordinary landscapes on Earth. 🗝️✨

For around $31 USD, you get four full days of unlimited access to thousands of sandstone pillars, misty valleys, ancient forests, and trails that will make you feel like you’ve stepped into another world. No other UNESCO World Heritage site offers this level of multi-day access at this price point.

The key to a stress-free experience is preparation. Understand the system, book in advance, bring your passport, budget for the extras, and arrive early. Do that, and the only thing you’ll be worrying about is which breathtaking viewpoint to photograph next. 📸🏔️

Now go get that ticket, scan that fingerprint, and lose yourself in the clouds! ☁️🌿💚

Found this ticket guide helpful? Share it with your travel companions so nobody shows up at the gate without their passport! Have a specific ticket question we didn’t cover? Drop it in the comments below—we’re here to help! 💬👇

🎫 장가계 국립삼림공원 입장권 완벽 가이드: 4일 우릉원 패스 자세히 알아보기