lwd responded with,

But they made the run in toward Hawaii at a considerably fast speed. And even 14 knots is more than most cargo ships can handle. "ILW"?

My first landing wave (1LW, not ILW, although that could work too as short for "Initial Landing Wave") arrives in 9 vessels each capable of 20+ knots.

Certainly, once surprise is no longer so vital, follow-on IJA troops for successive night's landing waves (2LW, 3LW and so on) will arrive off of Oahu after the Dec.6-7'41 groups, even though they left before, since they would be slower.

Was he? I thought he was ordered to abort the mission if discovered.

Only if "discovered" (which, in my ATL, I define as, discovered and reported because Yamamoto couldn't sink the discoveror before a radio mesage was sent out) more than 3 days out from Oahu.

Please don't forget that the OTL KB had 3 IJN submarines scout out some 60 miles ahead so that any potential discovering ship could be avoided instead and that in my ATL, the pre-approved cargo-liner Tatuta Maru would also be out ahead as a scout, leading the invasion towards Oahu.

In the OTL, Nagumo had the choise of returning to Japan if "discovered" two days out from Oahu but was historically ordered to attack anyway if reported only one day offshore.

Having an ATL Yamamoto along, in command, makes order alterations so much quicker and easier.

The northern Pacific was not completely empty.

There were indeed some American cargo vessels and a Yankee tanker or two running "lend/lease" thru Alaskan waters to the Russians in Vladivostock but they were never anywhere near Hawaiin waters.

They did choose that route because it was the least likely to be discovered but it was not empty.

Save for albatross and whales, for all practical Oahu attack purposes, I believe that it was. If you have a sourced list to the contrary, please present it to us all here for further investigation and lively, spirited discussion.

1) Not only does the battle fleet put to see but most of the rest of the navy as well as a huge transport fleet. Most of the latter of which are not usually needed for gunnery training.

As per the OTL, most of that ATL Japanese shipping is clearly heading south for Mindanao, Malaya and Thailand.

The Combined Fleet battleships taking gunnery practise in the (more southerly) Bonins is entirely in line with the Japanese habit of providing "distant support" for any of their naval ventures that might run into unexpected trouble. As per the OTL, I do still assign two IJN BBs to move much further south as a counter to the historical Force Z British BB moves between the Indian Ocean and Singapore.

2) It's a time or rather severe stress on the diplomatic front. People are expecting the Japanese to do something.

As per the OTL, my Japanese are indeed still openly moving large formations towards Mindanao, Malaya and Thailand. What other "something" would you prefer that they do as a realistic distraction cover for the invasion of Hawaii ?

3) Is radio silence typical for gunnery practice? If not then the there are going to have to be a lot of ships out there sending messages. However radio intercept types were pretty good at identifying what ships the messages came from at that point in time so trying to mimic that many individual ships is going to be problematic.

I don't believe that I have ever typed "radio silence" wrt faked CF gunnery practise in the Bonins. The term "radio deception techniques" was used IIRC. As per what Nagumo's Kido BUtai historically did. They left their regular radio operators behind in Japan, with orders to send fake radio messages daily that would make it seem like the IJN's biggest carriers were still in Japanese home waters. My ATL CF would do similar by sending the regular BB radio operators by ship to the Bonins from where they would transmitt truely inpressive BB gunnery scores back to Tokyo AND to the evesdropping Americans/British.