This is a two part mystery, the first part of which I'll speculate as to the answer, and the second part for which I'll ask for expert advice (or guesses!) to find the solution. Above we see a green of ultradwarf bermudagrass in the transition zone of Asia. By transition zone, I mean the area characterized by short but hot summers, and short but cold winters, with temperature average and extremes such that both cool-season (C₃) and warm-season (C₄) grasses can grow, but neither will thrive in all seasons. 

Referring to the image above, taken in mid-summer, we see what appears to be healthy grass on the right side of the green, and dead turf (or no turf) on the left side of the green. During the previous autumn season, both sides of the green were healthy and identical in appearance.

After the winter, when the temperatures warmed late in spring and the bermudagrass started to grow, only one side of the green grew. That mystery I'll solve; the right side of the green has a large amount of organic matter and thus a relatively high nutrient and water holding capacity, while the left side of the green is grown on pure sand, with very little water and essentially no nutrient hoding capacity. It seems that during the winter, it was not cold temperatures that killed the bermuda on the left side of the green, but rather a lack of water, and some type of desiccation.

But here, finally, is the mystery ... there are a few isolated areas on the "dead" side of the green that by mid-summer have recovered and are putting out stolons, rhizomes, and exhibiting extensive spreading. How did that happen?

And here is what happened:

@asianturfgrass Perhaps plugs from high OM side replaced in sandy side created micro-region of H20 and nutrient capacity? #startswithastolon

— PureTurf Consulting (@PureTurfC) August 7, 2012

On this putting green, changing the hole location the previous year caused some of the some from the high organic matter right side of the green to be changed in hole cores to the pure sand left side of the green. And that is where the grass survived the winter. 

There are four interesting things I would like to point out in this short video from a par 5 hole on a golf course in Central Japan. Three of these things, all potential mysteries on their own, I explain here, but for the fourth I asked for your assistance in solving the mystery.

1. The cart has no driver. This is a remote-controlled five-passenger cart, commonly found on golf courses in Japan and Korea. The cart takes the clubs around, allowing golfers to walk as much as they want to. I've always been concerned, being involved with course maintenance, about these quiet carts that can sneak up on you. One must be careful of what I have termed "ghost carts!" Note the concrete rails upon which the cart drives. This eliminates traffic damage from wear or compaction that would occur if the cart drove onto the turf.
2. The grass on the fairways is manilagrass (Zoysia matrella). The grass in the rough is japanese lawngrass (Zoysia japonica). At this course, as is common in Japan, there is no irrigation system in the fairway or the rough. Both species of zoysiagrass survive in this climate without supplemental irrigation. In this type of climate, without irrigation (or with judicious application of water), zoysia can provide a firm, bouncy playing surface with plenty of roll.
3. There are two greens on this hole! This course uses the two green system. Most courses with the two green system have the main green as creeping bentgrass with the subgreen being used less often. The subgreen is usually still creeping bentgrass but sometimes will be Z. matrella or bermudagrass. It is interesting at this course that the main green is Z. matrella and the subgreen is creeping bentgrass.
4. And now for the mystery. Why are there tee markers in the fairway? We can see that the golfers are not using them. Do you know what the markers are for?

Answer: These tees are called "playing 4 markers" or tokusetsu tees. Why "playing 4"? Because the purpose of those tees, commonly found on mountainous courses or on courses where the carts travel in a fixed (and pretty much unidirectional) route, is for one to hit from after a ball has been discovered to have gone out of bounds, or has been lost. Thus, when one hits from that point, one is "playing 4" or hitting one's fourth shot on the hole. 

Thanks to everyone who sent their answers to this mystery. I didn't realize it would be such a difficult one to guess. I, unfortunately, am too familiar with "playing 4" markers, having made use of them many times after errant drives. In addition to "playing 4" markers, some courses also place a flag or wind sock as an aiming point in the fairway. 

I'd heard of this problem from golf course superintendents in India and the Philippines, but hadn't seen it myself until last month. The grass is bermudagrass, the location is Sri Lanka, and when we dug into the soil and broke the soil apart, we saw these insects, in the video below, scurrying about. Can you identify what caused the bare spots on this green?

When we took a cup cutter plug from the green, we found it full of these active insects. 

These are termites. And they can be a recurring problem on some golf courses in tropical Asia. In fact, on some courses, termites are the major insect pest of putting greens.

You may be surprised at the answer. What grass is referred to here? From an article by Charles Vancouver Piper, first chairman of the USGA Green Section:

"________ is the best of all grasses in the South for fairways. It makes a dense, uniform turf even on pure sands and the leaves are stiff enough so that the ball is always well off the ground. The only other grass to compete with it is Bermuda; but under conditions where both will grow, _________ makes far superior turf."

Please leave a comment here or reply on twitter with the answer. I'll post the answer and some descriptive photos in a few days. And here it is:

The grass Piper was referring to is broadleaf carpetgrass, Axonopus compressus. Read the article here, from the December 1921 issue of the Green Section Record. Thanks to Captain Ben Sims, Jason Chennault, Jim Prusa, Scott McVey, and John Dempsey who all gave the answer of carpetgrass or the genus Axonopus. At right, the beautiful carpetgrass fairways of Laguna National Golf Club in Phuket.

Other guesses pretty much covered the spectrum of warm-season grasses used on fairways: kikuyugrass, buffalograss, St. Augustinegrass, seashore paspalum, bahiagrass, centipedegrass, and zoysiagrass. 

Carpetgrass was a bit of a surprise to be mentioned in this way, and I received a lot of comments from people who said they don't like the grass. Perhaps in an area with a lot of sunshine, and a relatively high maintenance budget, bermudagrass would be a better choice. But there are a lot of areas in the world where carpetgrass thrives and provides the type of playing surface that no other grass can. Just yesterday, I played the famous course at Nuwara Eliya, on stunning carpetgrass fairways (note that these are Axonopus affinis, similar but not the same species as referenced by Piper). See below. 

At this course, the fairways are pesticide free. Weed-free too, except for a few other naturalized grasses that come in. And in the salubrious climate of Nuwara Eliya, the fairways are mown less than five times a month.

For more information, have a look at this photo gallery, read this article about Manila's Wack Wack Golf and Country Club, and see this article I wrote about C.V. Piper, who made the stunning statement about carpetgrass in the first place!

What has happened here? Is it a disease, a fertilizer spill, different soil type, or perhaps a different type of grass?

This is on a golf course at an elevation of about 1,200 meters above sea level in Hawaii. We can also find this grass thriving at Dalat in Vietnam at 1,500 meters and at Kodaikanal in India at 2,000 meters.

Can you identify the type of grass? This species of grass is classified as a warm-season (C₄) grass although it has intermediate characteristics between cool- and warm-season grasses, performing best at moderate temperatures. Click the image below to view at a large size.

I'll post the answer in a few days . . . and here it is:

This is white clover (Trifolium repens) growing in a stand of kikuyugrass (Pennisetum clandestinum) on the island of Hawaii. Clover is a legume that can fix nitrogen in the soil, and legumes mixed with grass can provide about 36% of the grass's nitrogen*. So we see the kikuyugrass has turned green where it is mixed with clover, and it has grown thicker, and taller, and faster, in fact so much so that it has been scalped, as we see in the background. This is an indication that the grass would respond with more growth if more fertilizer nitrogen were applied. Thanks to Nadeem Zreikat in Australia and Andrew McDaniel in Japan for solving this mystery.

*Heichel, G.H. and K.I. Henjum. 1991. Dinitrogen fixation, nitrogen transfer, and productivity of forage legume-grass communities. Crop Science:31(202-208)

Can you identify the grass and the disease? This is a warm-season grass, in Southeast Asia, maintained at a mowing height of about 25 mm (1 inch). The average temperature during this season is about 17°C. Answer to be posted in a few days. 

Answer: This is seashore paspalum (Paspalum vaginatum) showing typical symptoms of dollar spot. Seashore paspalum grows most rapidly when average temperatures are more than 25°C. With the temperature at less than the optimum for seashore paspalum growth, but within the optimum range for dollar spot to grow, we can see this type of severe damage.

For some advice about dollar spot control on seashore paspalum in Asia, see this post from the Turf Diseases website:

Suggestions on the Right Maintenance for the Wrong Grass