You’re going to need a box.
Guzheng can be moved great distances with proper preparation. I've sent guzheng through the mail twice and been on the receiving end five times. Some of those instruments traveled over 3,000 miles. Here's what I have learned.
If you already have everything you need then shipping costs would come to about $150, possibly less if you aren’t shipping far. If you need to build or buy a box you might need another $100. If you need to buy a soft case, soft cases can be found for $50-$70 in the US. Hard cases aren’t usually available in the US.
Expect the guzheng to take about a week to ship domestically. It’s an over sized package and those take longer to transport. Also budget about 1-2 hours to prepare the guzheng for shipment and pack it properly plus the time to take it to your shipping center. Make sure you have someone who will receive it at the destination!
Airline shipment is usually not feasible. See below.
Loosen the strings. Just a quarter turn or so should be fine.
Prevents the instrument from breaking a string or over-stressing itself due to strange forces and temperature changes in transit.
Remove the bridges. Put them in a nice container. A small cardboard box with padding will suffice.
Prevents the bridges from marking the soundboard
Place any accessories such as the tuning wrench, electronic tuner, nails, and tape in the box of bridges. If they don't fit, place them in a box of their own.
Secure heavy objects, metal objects, and objects with edges like the tuning wrench. You want to prevent them from bouncing around and damaging other things.
Place the instrument in a protective case.
Protects the instrument from surface abrasions and contains the strings.
Acquire or make a shipping box.
Acquire End Supports.
Prevents the instrument from moving inside of its box and protects the ends in the event the corners get knocked in.
Place the wrapped instrument in a shipping box
Protects the instrument from collisions and surface abrasions.
Pad and cushion the inside of the box.
Protects the instrument from punctures and excessive jostling.
Final check - shake it. Does anything move around? If you hear something moving when you shake it something is loose. That can mean it will cause damage in transit. Unpack the guzheng, re-secure everything and check it again.
You have three choices for cases: A) a guzheng soft case or bag, B) a homemade protective wrap, or C) a hard case.
Shipping with a Soft Case
4a: Remove the bridges, loosen the strings, and place the instrument in the case and close it. Do not put anything in the pockets of the case - such items could be pressed into the instrument or bounce against it causing damage. Accessories such as the tuning wrench should be kept with the bridges in their own box.
Shipping with a custom wrap
4b: The point of a soft case and wrap are the same - to prevent the surface of the instrument from dust and light abrasions and to contain the strings. Cloth or some other soft material can be wrapped around the instrument. A waterproof soft case is the best but a wrap is better than nothing.
Shipping with a Hard Case
4c: Hard cases are a bit of a different story. Instruments can be shipped directly in their hard cases but there is some risk - the case itself may be damaged in shipping and some cases are not made with sufficient padding to prevent the instrument from bouncing around.
Some are rugged and padded enough to act as a shipping container however those are very rare outside of Asia. Common cases like the one above only have a cloth liner, meaning the instrument will bounce around inside. If you must ship by hard case then add additional padding to the interior so the instrument is snug (more cloth such bed sheets could work). Wrap the exterior in a tight-fitting box or in the protective plastic wrap you can get at airports and some shipping stores.
Be advised, however, that cases are typically heavy and will add to the shipping cost. Also, damage to the hard case is likely. I received an instrument shipped in just its 1980s hard case. The instrument made the trip but the end of the hard case had mostly detached. That said, I much prefer a damaged case to the damage a different instrument sustained when it was shipped in only a fabric case >:-(.
Getting a Box
Assuming you don’t have a hard case then the shipping box is what protects your instrument from the outside world. Ask teachers or any music stores in the area if they have spares. Industrial supply companies sell ‘telescoping’ boxes that can fit guzheng but those companies require you to purchase 10-15 boxes at once. At $10+ USD you are looking at $100+ just in cardboard. That’s the same price a guzheng owner was quoted when they asked a shipping company to make a single box for them. You’ll either need to sell the extra boxes to friends or find a reseller who will let you have just one box.
You could also build your own box. The finished box should be 10"x 17"x 66" if you are shipping in a wrap or soft case. The box should have enough overlapping cardboard to close and secure it. My estimates come out to a sheet of cardboard 88” x 62”, give or take, or 4+ strips of cardboard 17”+ wide by 88”+ long. Appliance stores might have large cardboard boxes you can take for materials. I don't recommend making a box yourself but it is possible.
End supports are crucial for keeping your instrument from bouncing around in transit. Guzheng are shipped with pre-formed Styrofoam end pieces. If you or someone you know receives a guzheng in the mail, save the end pieces in case you need to ship yours.
If you don't have end supports you'll need to make something similar through padding. Your goal is to accomplish two things: 1) keep the instrument from moving inside of its box, and 2) protect the ends of the instrument in the case a corner is crushed or pushed in. Use soft material to isolate the ends of the guzheng and a thin shell of harder material to shield the ends from damage.
Airline Shipment, Air Freight, Air Cargo
Airline shipment is usually not feasible. Most airlines limit oversized baggage to 80” combined dimensions. A full-sized guzheng in a hard case is about 67” x 8” x 14”. 67”+8”+14” = 89” combined.
You can apply for cargo shipping privileges to get past this restriction HOWEVER: Cargo needs to be able to survive drops of 1-2 feet and pressure of 60lbs per square foot as well as some exposure to the elements. A guzheng has about 5 square feet of surface area so its shipping container needs to survive being pressed by 300lbs for 12+ hours. Shipping as cargo may be as cheap as $100 domestically but you’ll need a wooden shipping crate - an additional $200 or so, possibly more.
Travel sized guzheng come in at about 77” combined so those could come with you. That will cost $75-$200 each way depending on the airline and the class you are flying. With good travel sizes available for $400 it can be cheaper to buy or rent a second instrument than to ship the one you own.
And there you have it!
If you already have everything you need then shipping costs would come to about $150, possibly less if you aren’t shipping far. If you need to build or buy a box you might need another $100. If you need to buy a case, soft cases can be found for $50-$70 in the US. Hard cases are nearly impossible.
Expect the guzheng to take about a week to ship domestically. It’s an over sized package and those typically take longer to transport. Also budget about 1-2 hours to prepare the guzheng for shipment and packing it properly, plus the time to take it to your shipping center. But remember there are no guarantees. Sending any package incurs risk. One shipping company employee asked me "Is it packed well? Could it survive a drop?" "How high of a drop?" With no hesitation she said "8 feet off the back of a truck."
Had I voiced my initial reaction it would have come out somewhere between "Ho-leeeee $%^&" and "It better not be $%&#$% dropped off the back of a $%&#$% truck!!" But their point stands: no amount of money from an insurance claim can make up for damage to a dear instrument. Pack your instrument well.