I've seen no documentation of this pre amplifier. The outside dates for this version are 1987 to very early 1990.
Given Shindo naming conventions it's likely that a 'Model 454' existed but I've found no documentation or images. If that unit existed the earliest expected date would be late 1985.
The Elegante appears to be exceptionally rare in the used market and it's not in the 1990 product lineup. It appears Shindo released a near identical 'Mazeris-Bellevus Model 454.'

Description:

None available

Specifications:

None available

Additional Details:

• Phono Inputs:
Phono 1 MM, 47KΩ, RCA Pin jack
Phono 2 MM, 100KΩ, RCA Pin jack
• Additional Inputs
4 (FM, TV,CD, AUX) x RCA Pin Jack
• Outputs
REC OUT : RCA Pin Jack
Line out: RCA Pin Jack
• Tube Complement (per channel):
1 x 12BH7A
2 x ECC83/5751, shielded
• Power Requirement: 100V AC, 15W, 50/60hz
• Captive power cable

This pre amplifier resembles the Elegante in most aspects but with the addition of rear-mounted gain controls. Knobs and switches have been relocated slightly.

Description, Shindo marketing catalog, 1990:

This preamplifier is an outstanding piece, exuding an elegant atmosphere with its refined and simple design. The circuit employs a SEPP-type cathode follower designed for compatibility with other amplifiers and minimizes cable loss by lowering the output impedance. Furthermore, on the rear panel we pursued high functionality with a beautiful design and the inclusion of a phono selector switch for easy switching. This is a high-quality preamplifier that reproduces delicate analog tones, purely and naturally.

Specifications, Shindo marketing catalog, 1990:

• Input Sensitivity/Impedance: PHONO MM, 47KΩ
• Maximum Allowable Input: 1,000mV (1kHz)
• Output Level: 10V/1kHz
• Total Harmonic Distortion: 0.04%
• PHONO RIAA Deviation: ±1dB (20Hz-20kHz)
• S/N Ratio: 90dB
• Input Terminal: RCA pin jack
• Output Terminal: RCA pin jack
• Power Supply: AC 100V/0.5A
• Power Consumption: AC 100V 50/60Hz, 50W
• Dimensions: 450(W) x 85(H) x 230(D) mm
• Weight: 7kg

Additional Details:

• Rear-mounted gain controls
• Phono Inputs:
Phono 1 MM, 47KΩ, RCA Pin jack
Phono 2 MM, 100KΩ , RCA Pin jack
• 4 x Line Inputs (FM, TV,CD, AUX) x RCA Pin Jack
• REC OUT : RCA Pin Jack
• Line out: RCA Pin Jack
• Tube Complement (per channel)
1 x 12BH7A
2 x ECC83/5751, shielded
• Power Requirement: 100V AC, 15W, 50/60hz
• Captive power cable

In October 1999 the Shindo website advertised the 'New' Mazeris Bellevus. This design removes the phono inputs and replaces them with a line input calibrated for CD players.
I've found no images for this product, it may have been made using existing chassis and faceplates making it indistinguishable from the prior variant.

Description, Shindo Laboratory website 2000:

We highly recommend this line amplifier to those who use only a CD player yet seek to fully realize its musical potential. It features a built-in output transformer that ensures stable output at 600 ohms impedance. Thanks to a significantly evolved circuit design, you can enjoy the depth and three-dimensional musicality of CDs, as well as the refined elegance of classical music.

* A version with a built-in CD matching transformer (for unbalanced operation) is also available.

Specifications, Shindo Laboratory website 2000:

• Input Impedance: CD: 250 kΩ (RCA pin jacks)
• Other Inputs: AUX, FM, TV (RCA pin jacks)
• Output Sensitivity/Impedance: 5 V / 600 Ω
• S/N Ratio: 90 dB
• Total Harmonic Distortion(at 1 V output)
100 Hz: 0.05%
1 kHz: 0.03%
10 kHz: 0.04%
• Frequency Response: 20 Hz – 20 kHz
• Power Consumption: AC 100 V, 50 W
• Power Supply: AC 100 V, 50/60 Hz
• Vacuum Tubes Used: 6X4 × 1, 6BM8 × 3
• Dimensions: W 450 × H 90 × D 300 mm
• Weight: 5 kg

Additional Details: