Given that the “relief” force consisted only of a one brigade from one of the stated divisions (the 7th) and a few regiments from another plus some non-divisional hanger ons, none of which were actually up to their established strength like Bob is pretending they were (Coox’s numbers indicate that they only had a maximum of 114 artillery pieces, not the rediculious 350-400 number posited above)...
The various units in the reinforcement group received final notice to move after the 23rd Division's failed counterattack on August 24th (in other words, from August 27th or so); they arrived by September 8/9, too late to participate in the fighting. They consisted of the 2nd Division (11,800 men), the 4th Division (8,315 men), the remainder of the 7th Division (10,308 including those troops already present - living or dead), elements of the 1st (4,980) and 8th (???) Divisions, the 5th Tank Regiment, 12 anti-tank batteries, a motorized mountain artillery regiment, 17 mountain artillery platoons, the 4th and 9th heavy field artillery regiments, 9 AA batteries, three engineer platoons, 21 transport companies, and the Manchukuo Motor Rail Unit. In terms of manpower these units were at peacetime strength but had their full complement of heavy equipment. Given this, the summary of their major weaponry would be as follows:
2nd Division (Type A) - 148 pieces, incl. 36 x 70mm battalion gun, 24 x 75mm regimental gun, 12 x 75mm field gun, 24 x 105mm howitzer, 12 x 150mm howitzer, 40 x 37mm AT gun
4th Division (Type A) - 148 pieces, same as above
12 AT batteries - 48 x 37mm AT gun
Mot. Mt. Arty Regiment - 24 x 75mm mountain gun
17 Mt. Arty Platoons - 34 x 75mm mountain gun
4th Hvy. Field Arty Regiment - 24 x 150mm howitzer
9th Hvy. Field Arty Regiment - 24 x 150mm howitzer
9 AA batteries - 36 x 75mm AA gun
Here is where things get a bit more ambiguous - from the figure of 4,980 men of the 1st Division transferred, we don't know if that included any of the field artillery regiment. Eye-balling it (Coox says this is half that Division), it looks about like 2 peacetime infantry regiments; the 1st being a Type A unit, that equates to 24 battalion guns, 16 regimental guns, and 24 anti-tank guns. We don't know how many men from the 8th Division were actually transferred, but it was certainly less than the 1st Division, probably only 1 regiment - 32 artillery pieces in total, excluding 50mm mortars. The 7th Division's effective forces included 2 more infantry regiments and its artillery regiment. Thus, from all this, we have a total of approximately 694 pieces, of which 354 are either regimental, mountain, or field artillery - a role which the Type 88 AA could fulfill as well. Depending on the status of each unit at a given time that total might have been higher or lower, but not by much.
The 5th Tank Regiment would have had a paper strength of about 60 tanks, but it's unclear how many of those were operable. The various divisions also sometimes had small tank units, but again I'm not sure about these divisions at this exact time.
There was some waffling on the part of IGHQ over whether or not to send the 5th and 14th Divisions from general reserve as well, but if the above were too late, they would have been too late^2.
..and it took weeks for the Japanese to scrape up and transport those forces...
Shown false by the above. Even with the various ditherings of the Japanese intelligence - battlefield reports generated an atmosphere in Tokyo HQ that was initially way more relaxed than it should have been, thus delaying any emergency orders - the reinforcement group was assembled in about 2 weeks.
...and this was after the Japanese had proved themselves incapable of logistically supporting even the 23rd Division despite only operating a third of the distance from their railheads as the much larger Soviet Forces...You’d probably have to screw things up on the Soviet side.
Correction - after the limited efforts of the 6th Army had proven incapable. The reinforcement group's transport companies and Rail Motor Unit alone had 1,500 trucks between them, 500 more than Komatsubara's entire force. Neither the Kwantung Army nor IGHQ had any intention of releasing more to the 6th Army, and orders to prepare the 23rd Division and its attachments for a long stalemate by stockpiling supplies for winter was sapping a large amount of what motorized strength they had.
If the Japanese headquarters in Tokyo had been more forthright about settling the issue at Khalkhin Gol by re-deploying some or all of the above units prior to August, unrestrained by fear of Soviet escalation elsewhere, it's possible they could have surpassed Stalin's "sunk costs" threshold in view of his overarching concerns in Europe and had their way with the border demarcation.